Austin, who calls China the U.S. military’s leading long-term challenge but has been forced to focus heavily on Russia this year, requested the telephone conversation with Gen. Wei Fenge after months of failed effort to speak with Gen. Xu Qiliang, the highest ranking uniformed officer in the Communist Party military structure.

Austin wanted to talk to Xu because, as deputy chairman of the Party’s Central Military Commission, which controls the People’s Liberation Army, Xu is more influential than Wei. But Beijing insisted on sticking to protocol and having Austin talk to Wei, who officially is his counterpart as defense minister but ranks below Xu in the hierarchy and has less military operational clout.

Austin’s predecessors had typically spoken with Wei, mostly recently on Aug. 6, 2020 when then-Defense Secretary Mark Esper raised with him a U.S. request for greater transparency on the origins of Covid-19 and other issues.

Austin had no expectation of a major breakthrough on key issues with Wei when he made the call on a secure telephone link that was established by the Pentagon and China’s Ministry of National Defense in 2008, according to a senior defense official who was involved in the arrangement and spoke on condition of anonymity in advance of the call, which has not been publicly announced.

Austin intended the call, which lasted about 45 minutes, as a follow-up to President Joe Biden’s video call with President Xi Jinping on March 18 in which he laid out stiff consequences the Chinese would face if they provided military or economic assistance for Russia’s war in Ukraine. The White House gave no indication that Biden received any assurances from the Chinese leader, and it was not immediately clear how Wei responded Wednesday.

For years Washington has portrayed China as seeking to reshape the international order to better assert its national interests and to build enough military strength to eventually supplant the United States as the dominant power in Asia.

The U.S.-China relationship has become more strained on multiple levels since the start of Biden’s presidency. Biden has repeatedly criticized China for military provocations against Taiwan, human rights abuses against ethnic minorities and efforts to squelch pro-democracy advocates in Hong Kong. U.S. officials also have expressed concern about signs that China is vastly increasing the size of its nuclear arsenal, although it remains fall smaller than America’s.

In Wednesday’s phone call, Austin echoed Biden’s messages on the importance of managing U.S.-Chinese strategic competition, including in the nuclear, space and cyber arenas, and improving crisis communications between the global powers, the senior defense official said.

Austin also raised U.S. concerns about what Washington views as Chinese military provocations against Taiwan, the island democracy that Beijing has insisted must ultimately be united with the Chinese mainland, the official said. He also expressed U.S. concerns about Chinese activities in the South China Sea and East China Sea and raised U.S. worries about North Korea’s nuclear weapons program.

The long-strained U.S.-China relationship may have reached a new low with the Russian invasion. At times, Beijing has sought to distance itself from the conflict but avoided directly criticizing Moscow. At other moments, Beijing’s actions have been provocative, including amplifying unverified Russian claims that Ukraine ran chemical and biological weapons labs with U.S. support.

American officials have expressed concern at the prospect of an Moscow-Beijing alliance of authoritarian states. In February, Xi and Russian President Vladimir Putin declared that the friendship between their counties “has no limits,” although it remains to be seen whether the subsequent Russian invasion of Ukraine has cooled Xi’s interest in closer ties.

The Biden administration’s first high-level meeting with Chinese officials came in March 2021 when Secretary of State Anton Blinken and Biden’s national security adviser, Jake Sullivan, met in Anchorage, Alaska, with their Chinese counterparts, who surprised their American hosts by complaining about a litany of issues.

Since then, there have been a succession of phone and video calls between Blinken and Chinese Foreign Minister Wang Yi but relatively few in-person meetings. Those calls have been dominated largely by issues of the day ranging from the situation in Afghanistan, Russia’s invasion of Ukraine, North Korea and Iran. Blinken has yet to visit China and the most senior U.S. diplomat to travel to the country has been Deputy Secretary of State Wendy Sherman.

AP Diplomatic writer Matthew Lee in Washington and AP writer Joe McDonald in Beijing contributed to this report.

The U.S. numbers alone are mounting: more than 12,000 weapons designed to defeat armored vehicles, some 1,400 shoulder-fired Stinger missiles to shoot down aircraft and more than 50 million rounds of ammunition, among many other things. Dozens of other nations are adding to the totals.

The Biden administration is preparing yet another, more diverse, package of military support possibly totaling $750 million to be announced in the coming days, a senior U.S. defense official said Tuesday. The official spoke on the condition of anonymity to discuss plans not yet publicly announced. The additional aid is a sign that the administration intends to continue expanding its support for Ukraine’s war effort.

These armaments have helped an under-gunned Ukrainian military defy predictions that it would be quickly overrun by Russia. They explain in part why Russian President Vladimir Putin’s army gave up, at least for now, its attempt to capture Kyiv, the capital, and has narrowed its focus to battling for eastern and southern Ukraine.

U.S. officials and analysts offer numerous explanations for why the Russians have had so little success interdicting Western arms moving overland from neighboring countries, including Poland. Among the likely reasons: Russia’s failure to win full control of Ukraine’s skies has limited its use of air power. Also, the Russians have struggled to deliver weapons and supplies to their own troops in Ukraine.

Some say Moscow’s problem begins at home.

“The short answer to the question is that they are an epically incompetent army badly led from the very top,” said James Stavridis, a retired U.S. Navy admiral who was the top NATO commander in Europe from 2009 to 2013.

The Russians also face practical obstacles. Robert G. Bell, a longtime NATO official and now a professor at the Sam Nunn School of International Affairs at Georgia Tech University, said the shipments lend themselves to being hidden or disguised in ways that can make them elusive to the Russians — “short of having a network of espionage on the scene” to pinpoint the convoys’ movements.

“It’s not as easy to stop this assistance flow as it might seem,” said Stephen Biddle, a professor of international and public affairs at Columbia University. “Things like ammunition and shoulder-fired missiles can be transported in trucks that look just like any other commercial truck. And the trucks carrying the munitions the Russians want to interdict are just a small part of a much larger flow of goods and commerce moving around in Poland and Ukraine and across the border.

“So the Russians have to find the needle in this very big haystack to destroy the weapons and ammo they’re after and not waste scarce munitions on trucks full of printer paper or baby diapers or who knows what.”

Even with this Western assistance it’s uncertain whether Ukraine will ultimately prevail against a bigger Russian force. The Biden administration has drawn the line at committing U.S. troops to the fight. It has opted instead to orchestrate international condemnation and economic sanctions, provide intelligence information, bolster NATO’s eastern flank to deter a wider war with Russia and donate weapons.

In mid-March, a Russian deputy foreign minister, Sergei Ryabkov, said arms shipments would be targeted.

“We warned the United States that pumping weapons into Ukraine from a number of countries as it has orchestrated isn’t just a dangerous move but an action that turns the respective convoys into legitimate targets,” he said in televised remarks.

But thus far the Russians appear not to have put a high priority on arms interdiction, perhaps because their air force is leery of flying into Ukraine’s air defenses to search out and attack supply convoys on the move. They have struck fixed sites like arms depots and fuel storage locations, but to limited effect.

On Monday, the Russians said they destroyed four S-300 surface-to-air missile launchers that had been given to Ukraine by an unspecified European country. Slovakia, a NATO member that shares a border with Ukraine, donated just such a system last week but denied it had been destroyed. On Tuesday, the Russian Ministry of Defense said long-range missiles were used to hit two Ukrainian ammo depots.

As the fighting intensifies in the Donbas and perhaps along the coastal corridor to the Russian-annexed Crimean Peninsula, Putin may feel compelled to strike harder at the arms pipeline, which Ukrainian President Volodymyr Zelenskyy has called vital to his nation’s survival.

In the meantime, a staggering volume and range of war materiel is arriving almost daily.

“The scope and speed of our support to meeting Ukraine’s defense needs are unprecedented in modern times,” said John Kirby, the Pentagon press secretary. He said the approximately $2.5 billion in weapons and other material that has been offered to Ukraine since the beginning of the Biden administration is equivalent to more than half of Ukraine’s normal defense budget.

One example: The Pentagon says it has provided more than 5,000 Javelin missiles, which are among the world’s most effective weapons against tanks and other armored vehicles — and can even take down a low-flying helicopter. The missile, shaped like a clunky dumb bell and weighing 50 pounds (23 kilograms), is fired by an individual soldier; from its launch tube it flies up at a steep angle and descends directly onto its target in what its known as a curveball shot — hitting the top of a tank where its armor is weakest.

The specific routes used to move the U.S. and other Western materials into Ukraine are secret for security reasons, but the basic process is not. Just this week, two U.S. military cargo planes arrived in Eastern Europe with items ranging from machine guns and small arms ammunition to body armor and grenades, the Pentagon said.

A similar load is due later this week to complete delivery of $800 million in assistance approved by President Joe Biden just one month ago. The weapons and equipment are offloaded, moved onto trucks and driven into Ukraine by Ukrainian soldiers for delivery.

Kirby said the material sometimes reaches troops in the field within 48 hours of entering Ukraine.

Russia has turned to Gen. Alexander Dvornikov, 60, one of Russia’s most experienced military officers and — according to U.S. officials — a general with a record of brutality against civilians in Syria and other war theaters. The senior official who identified the new commander was not authorized to be identified and spoke on condition of anonymity.

But the White House national security adviser, Jake Sullivan, said “no appointment of any general can erase the fact that Russia has already faced a strategic failure in Ukraine.”

“This general will just be another author of crimes and brutality against Ukrainian civilians,” Sullivan told CNN’s “State of the Union.” “And the United States, as I said before, is determined to do all that we can to support Ukrainians as they resist him and they resist the forces that he commands.”

The decision to establish new battlefield leadership comes as Russia gears up for what is expected to be a large and more focused push to expand Russian control in the Donbas and follows a failed opening bid to conquer Kyiv, the capital.

Dvornikov gained prominence while leading the Russian group of forces in Syria, where Moscow has waged a military campaign since 2015 to shore up President Bashar Assad’s regime during a devastating civil war.

Dvornikov is a career military officer and has steadily risen through the ranks after starting as a platoon commander in 1982. He fought during the second war in Chechnya and took several top positions before being placed in charge of the Russian troops in Syria in 2015.

In 2016, Putin awarded Dvornikov the Hero of Russia medal, one of the country’s highest awards. Dvornikov has served as the commander of the Southern Military District since 2016.

Sullivan described the general as having a record of brutality against civilians in Syria and said “we can expect more of the same in this theater.” But he stressed that the U.S. strategy remains the same in providing Ukraine the military and logistical support it needs.

The prospect of a bigger U.S. military footprint in Europe is a remarkable turnaround from just two years ago.

In 2020, President Donald Trump ordered thousands of American troops out of Germany as part of his argument that Europeans were undeserving allies. Just days after taking office, President Joe Biden stopped the withdrawal before it could start, and his administration has stressed NATO’s importance even as Biden identifies China as the main long-term threat to U.S. security.

Then came Russia’s invasion of Ukraine.

“We are in a new era of sustained confrontation with Russia,” says Alexander Vershbow, a former U.S. ambassador to Russia and former deputy secretary-general of NATO. He argues that the United States, in cooperation with NATO allies, will need to establish a more muscular stance to deal with a more threatening Russia. That is especially so in Eastern Europe, where Russia’s proximity poses a problem for the three Baltic nations that are former Soviet states.

Defense Secretary Lloyd Austin was flying to Europe on Tuesday for his second recent round of Ukraine consultations at NATO headquarters in Brussels. He also will travel to two Eastern European NATO countries — Slovakia, which borders Ukraine, and Bulgaria, which does not. After a NATO meeting last month, Austin visited two other allies on the eastern flank — Poland and Lithuania.

As Austin was en route, NATO Secretary-General Jens Stoltenberg made it clear Tuesday that the 30-nation military alliance is set to radically change its security stance in Europe in response to Russia’s war on Ukraine. He said defense ministers will discuss possible changes when they meet Wednesday.

“We need to reset our military posture for this new reality,” Stoltenberg told reporters. “On land, this could include substantially more forces in the eastern part of the alliance, at higher readiness, and with more prepositioned equipment.”

He added that NATO “will also consider major increases to our air and naval deployments, strengthening our integrated air and missile defense, reinforcing our cyber defenses, and holding more and larger exercises.”

In just the past two months, the U.S. presence in Europe has jumped from about 80,000 troops to about 100,000, which is nearly as many as were there in 1997 when the United States and its NATO allies began an expansion of the alliance that Putin says threatens Russia and must be reversed. By comparison, in 1991, the year the Soviet Union dissolved, the United States had 305,000 troops in Europe, including 224,000 in Germany alone, according to Pentagon records. The number then dropped steadily, reaching 101,000 in 2005 and about 64,000 as recently as 2020.

This year’s U.S. troop additions are billed as temporary, but there’s no certainty how long they’ll stay. They include an armored brigade of the 1st Infantry Division, totaling about 4,000 soldiers, to Germany, and a similar-size infantry brigade of the 82nd Airborne Division, to Poland. Numerous Army headquarters units also have been sent to Poland and Germany. Austin also sent F-35A fighter jets to NATO’s eastern flank and Apache attack helicopters to the Baltic states.

A recent Pentagon review of its worldwide military presence concluded that troop levels and positions in Europe were about right. But in testimony before a House committee several days after Putin invaded Ukraine, Mara Karlin, a senior Pentagon official who oversaw the 2021 review, said that conclusion will have to be reconsidered.

The Pentagon must “ensure that we’ve got deterrence of Russia and that we can absolutely 150% say that NATO is safe and secure,” not just in light of Russia’s invasion but for the longer term, she said March 1.

Putin’s war in Ukraine has prompted a rethinking of regional defense needs not just by Washington but also some European allies, including Germany, which last month broke with a longstanding policy of not exporting weapons to conflict zones by sending anti-tank and anti-aircraft weapons to Ukraine. Germany also committed to a much bigger defense budget.

“A new reality,” Chancellor Olaf Scholz declared.

Putin has not only demanded that Ukraine disavow its ambition to join NATO but also insisted the alliance withdraw its forces from NATO’s eastern flank — demands the U.S. and NATO reject as counter to the fundamental rights of nations to decide their foreign relations for themselves and of NATO’s basic commitment to provide security for all members equally.

If Russia were to take control of the entirety of Ukraine, it would be on the border of additional NATO countries, including Romania, Slovakia and Hungary. Poland and Lithuania already share a land border with the Russian enclave of Kaliningrad, headquarters of the Baltic Fleet of the Russian Navy. There is concern that Putin could decide to make a play for control of that 60-mile-long land corridor, known as the Suwalki Gap, that connects Kaliningrad to Belarus.

Vershbow, the former deputy NATO secretary-general who is now a distinguished fellow at the Atlantic Council, recommends that the U.S. and NATO move beyond their current reliance on light, battalion-size battle groups in Eastern Europe to instead deploy heavier, larger and permanent forces there.

Such a transition on NATO’s eastern flank is just the sort of thing Putin says is a threat to Russia and says he will no longer tolerate. He has demanded a return to the arrangements that existed in 1997, when the NATO-Russia Founding Act was signed.

In that document, Moscow acknowledged that NATO would go ahead with plans to invite Poland, Hungary and the Czech Republic to join the alliance. Notably, the document also said that “in the foreseeable security environment,” NATO would forgo “additional permanent stationing of substantial combat forces on the territory of new members.”

Does that foreclose the option of a U.S. troop buildup in Eastern Europe? No, says a new report by the Atlantic Council’s Scowcroft Center for Strategy and Security. It argues that the restrictions on NATO’s military presence in Eastern Europe as described in the 1997 NATO-Russia Founding Act are irrelevant in light of Russia’s invasion of Ukraine.

“We are in new, dangerous territory — a period of sustained tensions, military moves and countermoves, and major intermittent military crises in the Euro-Atlantic area that will ebb and flow for at least the remainder of the 2020s, if not longer,” the report says.

The officials, who discussed internal assessments of the Russian buildup on condition they not be identified, sketched out a series of indicators suggesting Putin intends an invasion in coming weeks, although the size and scale are unclear. They stressed that a diplomatic solution appears to remain possible.

Among those military indicators: an exercise of Russia’s strategic nuclear forces that usually is held each fall was rescheduled for mid-February to March. That coincides with what U.S. officials see as the most likely window for invasion. The officials made no suggestion that a prospective conflict would involve the use of nuclear weapons, but the Russian exercise — likely involving the test-launching of unarmed long-range missiles on Russian territory — could be used as a message aimed at deterring the West from intervening in Ukraine.

U.S. officials have said in recent weeks that a Russian invasion could overwhelm Ukraine’s military relatively quickly, although Moscow might find it difficult to sustain an occupation and cope with a potential insurgency.

The ongoing Russian buildup comes as the Biden administration has been disclosing intelligence in hopes of preemptively countering Russian disinformation and blocking Putin’s plans for creating a pretext for an invasion. But it has come under criticism for not providing evidence to back up many of its claims.

On Saturday, The New York Times and The Washington Post said officials were warning that a full Russian invasion could lead to the quick capture of Kyiv and potentially result in as many as 50,000 casualties. A U.S. official confirmed that estimate to The Associated Press. But it’s not clear how U.S. agencies determined those numbers, and any predictions about how an invasion would proceed and the human cost it would inflict are inherently uncertain given the vagaries of war.

President Joe Biden has said he will not send U.S. troops to Ukraine to fight a war. He has, however, ordered additional forces, including headquarters personnel and combat troops, to Poland and Romania to reassure those NATO allies that Washington would fulfill its treaty commitment to respond to Russian aggression against NATO territory. Ukraine is not a NATO member but receives U.S. and allied military support and training.

Army officials on Saturday announced that Maj. Gen. Christopher Donahue, the commanding general of the 82nd Airborne Division, arrived in Poland. About other 1,700 soldiers from the 82nd Airborne are deploying to Poland from Fort Bragg, North Carolina, and 300 soldiers are deploying from Bragg to Germany. In addition, 1,000 Germany-based soldiers are shifting to Romania.

With growing nervousness in Eastern Europe over Russia’s buildup, much attention is focused on its placement of thousands of troops in Belarus, which shares a border not only with Ukraine but also with three NATO nations — Poland, Lithuania and Latvia. The Biden administration may soon shift some more troops within Europe to allied nations on NATO’s eastern flank, a U.S. official said Saturday without specifying which nations.

Defense Secretary Lloyd Austin said last week that Putin could use any portion of the force he has assembled along Ukraine’s borders to seize Ukrainian cities and “significant territories” or to carry out “coercive acts or provocative political acts” like the recognition of breakaway territories inside Ukraine.

More recently, other U.S. officials provided a more detailed breakdown of Russia’s continuing force buildup, of U.S. assessments of prospects for war, and of the U.S. view of Putin’s approach to the crisis.

The officials reiterated what other Biden administration officials have been saying for weeks — that they don’t believe Putin has made a final decision to invade Ukraine. But it appears possible that the Russian leader set his intentions and is waiting until the last moment to give the go-ahead for an invasion.

Officials sketched out the disposition of Russian forces that have been deployed toward Ukraine’s borders over the past several months, creating what Western officials see as the threat of a full-scale invasion despite repeated assertions by senior Russian officials that they do not intend to attack unprovoked.

As of Friday, the officials said, the Russian army has put in place near Ukraine a total of 83 “battalion tactical groups,” each of which is roughly equivalent in size to an American battalion of between 750 and 1,000 soldiers. That is an increase from 60 battalion tactical groups in position just two weeks ago, they said.

Another 14 battalion tactical groups are on their way to the border area from other parts of Russia, the officials said. Two officials said the U.S. assesses that Russia would want a total of between 110 and 130 battalion tactical groups for use in a full-scale invasion, but Putin could decide on a more limited incursion. Including support units, Russia might be aiming to have 150,000 troops in place for a full-scale invasion, one official said, adding that the ongoing buildup could reach that level in the next couple of weeks.

Depending on Putin’s ultimate objective, the Russian forces could attack Kyiv directly by moving south from current positions in southern Belarus. He might also send forces across the Russian border into eastern and southern Ukraine if his intent is to fracture and destroy a large portion of the Ukrainian army, the officials said.

On the lower end of the scale of military action, Putin might order sabotage, cyberattacks and other destabilizing actions inside Ukraine with the goal of removing the current government in Kyiv, officials have said.

Associated Press writer Nomaan Merchant contributed to this report.

The rationale for not directly joining a Russia-Ukraine war is simple. The United States has no treaty obligation to Ukraine, and war with Russia would be an enormous gamble, given its potential for expanding in Europe, destabilizing the region, and escalating to the frightening point of risking a nuclear exchange.

Doing too little has its risks, too. It might suggest an acquiescence to future Russian moves against other countries in eastern Europe, such as the Baltic states of Estonia, Latvia and Lithuania, although as NATO members those three have security assurances from the United States and the rest of the alliance.

Secretary of State Antony Blinken, who is in Europe this week to speak with officials in Ukraine, consult NATO allies and then meet Friday with his Russian counterpart, has asserted “an unshakable U.S. commitment to Ukraine’s sovereignty and territorial integrity.” But he has not publicly defined the limits of that commitment.

How far, then, might the United States and its allies go to help Ukraine defend itself if the buildup of Russian forces along Ukraine’s borders leads to an invasion?

Why not contest a Russian invasion?

Going to war against Russia in Ukraine could tie up U.S. forces and resources for years and take a heavy toll in lives with an uncertain outcome at a time when the Biden administration is trying to focus on China as the chief security threat.

On Wednesday, Biden said it was his “guess” that Russian President Vladimir Putin will end up sending forces into Ukraine, although he also said he doesn’t think Putin wants all-out war. Biden did not address the possibility of putting U.S. ground troops in Ukraine to stop an invasion, but he previously had ruled that out.

Biden said he is uncertain how Putin will use the forces he has assembled near Ukraine’s border, but the United States and NATO have rejected what Moscow calls its main demand — a guarantee that the Western alliance will not expand further eastward. Russia annexed the Crimean Peninsula from Ukraine in 2014 after the ouster of Ukraine’s Moscow-friendly leader and also intervened in eastern Ukraine that year to support a separatist insurgency. More than 14,000 people have been killed in nearly eight years of fighting there.

The stakes in Ukraine are high — militarily and politically. Lawmakers have intensified their criticism of Biden’s approach to Putin. Sen. James Inhofe of Oklahoma, the ranking Republican on the Senate Armed Services Committee, accused Biden of “handwringing and appeasement,” but he has not urged sending combat troops. Rep. Jim Himes, a Connecticut Democrat who sits on the House Intelligence Committee, called for an urgent “nonstop airlift” of military equipment and trainers into Ukraine.

Philip Breedlove, a retired Air Force general who served as the top NATO commander in Europe from 2013 to 2016, said in an interview he does not expect or recommend that the United States send combat troops into Ukraine. Instead, Washington and its allies should be looking for ways to help Ukraine defend its own airspace and territorial waters, where it faces overwhelming Russian superiority, he said.

“Those are things we should be considering as an alliance and as a nation,” he said. “If Mr. Putin is allowed to invade Ukraine and there were to be little or no consequence, we will see more of the same.”

What are Biden’s other options?

Given its clear military inferiority, Ukraine could not prevent Russian forces from invading. But with help from the United States and others, Ukraine might deter Putin from acting if he were convinced that the costs would be too high.

“The key to thwarting Russian ambitions is to prevent Moscow from having a quick victory and to raise the economic, political, and military costs by imposing economic sanctions, ensuring political isolation from the West, and raising the prospect of a prolonged insurgency that grinds away the Russian military,” Seth Jones, a political scientist, and Philip Wasielewski, a former CIA paramilitary officer, wrote in a Jan. 13 analysis for the Center for Strategic and International Studies.

The Biden administration has suggested it is thinking along similar lines.

How is the US supporting Ukraine’s military now?

Pentagon press secretary John Kirby says there are about 200 National Guard soldiers in Ukraine to train and advise local forces, and on Tuesday he said there are no plans to augment their number. There also are an undisclosed number of U.S. special operations troops providing training in Ukraine. Kirby wouldn’t say whether the U.S. soldiers would pull out in the event of a Russian invasion, but he said the Pentagon would “make all the appropriate and proper decisions to make sure our people are safe in any event.”

The administration said Wednesday it is providing a further $200 million in defensive military aid to Ukraine. Since 2014 the United States has provided Ukraine with about $2.5 billion in defense assistance, including anti-tank missiles and radars.

How might the US help Ukraine after an invasion?

It’s not clear. National security adviser Jake Sullivan said last week that the U.S. would “dramatically ramp up” support for Ukraine’s “territorial integrity and sovereignty.” But he did not spell out how that might be done.

The administration says it also is open to sending military reinforcements to NATO allies on the eastern front who want American reassurance.

Jones and Wasielewski say that in addition to implementing severe sanctions against Russia in the event of an invasion, the United States should provide Ukraine with a broad range of military assistance at no cost. This would include air defense, anti-tank and anti-ship systems; electronic warfare and cyber defense systems; small arms and artillery ammunition, and other items.

“The United States and NATO should be prepared to offer long-term support to Ukraine’s resistance no matter what form it ends up taking,” they wrote. This aid could be delivered overtly with the help of U.S. troops, including special operations forces, or it could be a CIA-led covert action authorized by President Biden, they added.

That would carry the risk of putting U.S. personnel in the line of fire — and drawing the United States into the very combat it’s determined to avoid.

The strikes against the launch sites apparently were conducted by U.S. forces, but a statement issued by the coalition did not specify who carried them out. The statement offered few details beyond saying the sites “posed an imminent threat in the vicinity of Green Village, Syria,” and were struck in self defense.

Green Village, just east of the Euphrates River, is an installation used by some of the several hundred U.S. forces in Syria.

Pentagon spokesman John Kirby said airstrikes were not used against the launch sites. He did not elaborate.

“One of the reasons these sites were hit was we had reason to believe that they were going to be used as launch sites for attacks on Green Village,” Kirby said. “So clearly our men and women remain in harm’s way and we have to take that threat very seriously and we always have the right of self defense.”

Kirby said he could not comment on which group may have intended to use the rocket sites. The pre-emptive attack on the sites followed two separate incidents this week in Iraq in which explosives-laden drones were shot down before they could attack an Iraqi military base housing U.S. troops in western Iraq and a facility housing U.S. advisers at Baghdad airport.

Commenting on those drone incidents in Iraq on Monday and Tuesday, Kirby said the United States has not conclusively determined who was behind them, but he added, “these kinds of attacks are very much in keeping with the kind of attacks we’ve seen from Iran-backed militias in Iraq and in Syria, and so obviously our working-level assumption is that such groups were responsible for these.”

A January 2020 U.S. drone strike at Baghdad’s airport killed Gen. Qassim Soleimani, who was the head of Iran’s elite Quds Force, and Abu Mahdi al-Muhandis, deputy commander of Iran-backed militias in Iraq.

Pro-Iran Shiite factions in Iraq have vowed revenge for the killings.

The United States has about 2,500 troops in Iraq acting as trainers and advisers to Iraqi security forces.

A federal judge in Texas has granted a preliminary injunction stopping the Navy from acting against 35 sailors for refusing on religious grounds to comply with an order to get vaccinated against COVID-19.

The injunction is a new challenge to Defense Secretary Lloyd Austin’s decision to make vaccinations mandatory for all members of the military. The vaccination requirement allows for exemptions on religious and other grounds, but none of the thousands of requests for religious waivers so far have been granted.

There was no indication that the order would affect service members beyond the 35 sailors who sued Austin and the Navy. The Pentagon had no immediate response to a request for comment.

Well over 90% of the military has been fully vaccinated against COVID-19, including at least 98.5% of active and reserve members of the Navy. Austin asserts that vaccines are a valid and necessary medical requirement to protect service members and their families and ensure the combat readiness of the force.

In his decision Monday, U.S. District Judge Reed O’Connor wrote that the Navy’s process for considering a sailor’s request for a religious exemption is flawed and amounts to “theater.”

O’Connor, who was appointed by President George W. Bush, wrote that the group of 35 sailors who sued the government in November and sought a preliminary injunction against the Navy have a right on religious and First Amendment grounds to refuse the vaccination order.

“The Navy servicemembers in this case seek to vindicate the very freedoms they have sacrificed so much to protect,” O’Connor wrote. “The COVID-19 pandemic provides the government no license to abrogate those freedoms. There is no COVID-19 exception to the First Amendment. There is no military exclusion from our Constitution.”

The O’Connor injunction was first reported by The Washington Post.

Without commenting on the case in Texas, Pentagon spokesman John Kirby in December defended the validity of the military service’s processes for considering religious exemptions.

“Each exemption asked for on religious grounds is evaluated by a chaplain, by a chain of command, by medical experts and is given quite a lot of thought, and they’re all decided case by case individually,” he said Dec. 21.

In his decision in favor of the injunction sought by the 35 Navy sailors, O’Connor wrote that they objected to being vaccinated on four grounds: “opposition to abortion and the use of aborted fetal cell lines in development of the vaccine; belief that modifying one’s body is an affront to the Creator; divine instruction not to receive the vaccine, and opposition to injecting trace amounts of animal cells into one’s body.”

“Plaintiffs’ beliefs about the vaccine are undisputedly sincere, and it is not the role of this court to determine their truthfulness or accuracy,” the judge wrote.

The sailors who suing are members of the Naval Special Warfare Command, including SEALs. The suit was filed by First Liberty Institute, a nonprofit that focuses on defending religious liberty.

In the early stages of the pandemic, the Navy struggled with one particularly critical COVID-19 outbreak. Hundreds of sailors aboard the aircraft carrier Theodore Roosevelt were infected, starting in late March while on a deployment to Vietnam and elsewhere in Asia. The ship was taken out of operation at Guam, its commanding officer was relieved of duty and the crisis led to the resignation of acting Navy Secretary Thomas Modly.

Since then, the Navy and other services have managed to avoid major disruptions.

In December 2021, officials said about two dozen sailors on board the littoral combat ship Milwaukee, or roughly 25% of the ship’s crew, had tested positive for COVID-19, keeping the vessel sidelined in port at Naval Station Guantanamo Bay in Cuba. On Monday, the Navy announced that the ship had returned to sea.

AP writer Eric Tucker contributed to this report.

Then China happened — revelations about its expanding nuclear force and talk of potential war with Taiwan.

And then Russia happened — signs that it might be preparing to invade Ukraine.

Now, major shifts in U.S. nuclear weapons policy seem much less likely, and while Biden may insist on certain adjustments, momentum toward a historic departure from the Trump administration’s policy appears to have stalled.

The outlook will be clearer when the Biden administration completes its so-called nuclear posture review — an internal relook at the numbers, kinds and purposes of weapons in the nuclear arsenal, as well as the policies that govern their potential use. The results could be made public as early as January.

The biggest unknown is how forcefully Biden will weigh in on these questions, based on White House calculations of the political risk. During his years as vice president, Biden talked of new directions in nuclear policy. But heightened concerns about China and Russia would seem to improve the political leverage of Republicans seeking to portray such change as a gift to nuclear adversaries.

Russia became a more urgent focus of Biden’s attention after President Vladimir Putin in recent weeks sent an estimated 100,000 troops to positions near Ukraine’s border and demanded U.S. security guarantees. Biden and Putin discussed Ukraine by phone on Thursday, and senior American and Russian officials are scheduled to follow up with more detailed talks in Geneva on Jan. 9-10.

Tom Z. Collina, policy director at Ploughshares Fund, an advocate for nuclear disarmament, says the China and Russia problems complicate the politics of Biden’s nuclear review but should not stop him from acting to reduce nuclear dangers.

“We do not want a new nuclear arms race with either nation and the only way to prevent that is with diplomacy,” Collina said. “We must remember the main lesson we learned in the Cold War with Russia — the only way to win an arms race is not to run.”

In March, in what the White House called interim national security guidance, Biden said China and Russia had changed “the distribution of power across the world.”

“Both Beijing and Moscow have invested heavily in efforts meant to check U.S. strengths and prevent us from defending our interests and allies around the world,” the guidance said. Biden pledged to counter with actions to strength the United States at home, repair its alliances abroad and elevate the role of diplomacy. Nuclear weapons were mentioned only briefly.

“We will take steps to reduce the role of nuclear weapons in our national security strategy,” the guidance said without offering details, while also ensuring a safe and reliable U.S. nuclear force and seeking arms control opportunities.

Since then, worries about China and Russia have only increased. Private satellite imagery revealed last summer that China was building large numbers of new underground silos for nuclear missiles, and in November, a Pentagon report said China may quadruple the size of its nuclear stockpile by 2030.

“Because of what China has done, it has really changed the complexion of this review,” says Robert Soofer, who was the Pentagon’s top nuclear policy official during the Trump administration and led a 2018 nuclear review.

“Rather than it being a review that examines reducing the role of nuclear weapons and even eliminating a leg of the triad, now they’ve been obliged to basically stay the course and determine how to tweak it at the margins.”

In June, even before the latest Russian troop buildup near Ukraine, the Pentagon’s policy chief, Colin Kahl, said the outlook for U.S. nuclear policy was colored not only by China’s nuclear ambitions but also by “real anxiety” among U.S. allies in Europe over Russian defense and nuclear policy.

“And so, obviously Russia is the wolf closest to the shed as it relates to the nuclear issue, but close behind is China’s desire to grow their nuclear arsenal, both quantitatively and qualitatively,” Kahl said June 23 at a nuclear policy conference sponsored by the Carnegie Endowment for International Peace.

Kahl did not preview the policy review outcome, but he said it is intended to fit inside a broader defense strategy, which also is to be published early in 2022.

The Pentagon has not publicly discussed details of the nuclear review, but the administration seems likely to keep the existing contours of the nuclear force — the traditional “triad” of sea-, air- and land-based weapons, which critics call overkill. It also may embrace a $1 trillion-plus modernization of that force, which was launched by the Obama administration and continued by Trump.

It’s unclear whether Biden will approve any significant change in what is called “declaratory policy,” which states the purpose of nuclear weapons and the circumstances under which they might be used.

The Obama administration, with Biden as vice president, stated in 2010 that it would “only consider the use of nuclear weapons in extreme circumstances to defend the vital interests of the United States or its allies and partners.” It did not define “extreme circumstances.”

Eight years later, the Trump administration restated the Obama policy but got more specific. “Extreme circumstances could include significant non-nuclear strategic attacks. Significant non-nuclear strategic attacks include, but are not limited to, attacks on the U.S., allied, or partner civilian population or infrastructure, and attacks on U.S. or allied nuclear forces, their command and control, or warning and attack assessment capabilities.”

Some believed that Biden as president would go a different direction, following his own advice on a “no first use” pledge. He said in a January 2017 speech: “Given our non-nuclear capabilities and the nature of today’s threats, it’s hard to envision a plausible scenario in which the first use of nuclear weapons by the United States would be necessary, or make sense.”

But some argue that China and Russia this year have changed “today’s threats,” perhaps keeping Biden on a cautious path.

Marine Gen. Frank McKenzie, head of U.S. Central Command, said in an interview with The Associated Press that the departure of U.S. military and intelligence assets from Afghanistan has made it much harder to track al-Qaida and other extremist groups inside Afghanistan.

“We’re probably at about 1 or 2 percent of the capabilities we once had to look into Afghanistan,” he said, adding that this makes it “very hard, not impossible” to ensure that neither al-Qaida nor the Islamic State group’s Afghanistan affiliate can pose a threat to the United States.

Speaking at the Pentagon, McKenzie said it’s clear that al-Qaida is attempting to rebuild its presence inside Afghanistan, which was the base from which it planned the Sept. 11, 2001, attacks against the United States. He said some militants are coming into the country through its porous borders, but it is hard for the U.S. to track numbers.

The U.S. invasion that followed the Sept. 11 attacks led to a 20-year war that succeeded initially by removing the Taliban from power but ultimately failed. After President Joe Biden announced in April that he was withdrawing completely from Afghanistan, the Taliban systematically overpowered Afghan government defenses and seized Kabul, the capital, in August.

McKenzie and other senior U.S. military and national security officials had said before the U.S. withdrawal that it would complicate efforts to keep a lid on the al-Qaida threat, in part because of the loss of on-the-ground intelligence information and the absence of a U.S.-friendly government in Kabul. The U.S. says it will rely on airstrikes from drones and other aircraft based beyond Afghanistan’s borders to respond to any extremist threats against the U.S. homeland.

McKenzie said no such strikes have been conducted since the U.S. completed its withdrawal from Afghanistan on Aug. 30. He added that America’s ability to conduct such strikes is based on the availability of intelligence, overhead imagery and other information and communications, “and that architecture is still being developed right now.”

Al-Qaida is among numerous extremist groups inside Afghanistan. After 2001, it lost most of its numbers and its ability to directly threaten U.S. territory, but McKenzie said it retains “an aspirational desire” to attack the United States. During their first period of rule in Kabul, from 1996 to 2001, the Taliban gave haven to al-Qaida and refused Washington’s demand after 9/11 to expel the group and turn over its leader, Osama bin Laden. The Taliban and al-Qaida have maintained ties ever since.

“So we’re still trying to sort out exactly how the Taliban is going to proceed against them, and I think over the month or two it’ll become a little more apparent to us,” he said.

Similarly, McKenzie said it’s not yet clear how strongly Taliban will go after the Islamic State group, also known as ISIS, which has violently attacked the Taliban across the country. The United States blamed ISIS for an Aug. 26 suicide bombing at Kabul airport that killed 13 American service members in the final days of the U.S. evacuation.

ISIS was “reinvigorated,” McKenzie said, by the release of numerous ISIS fighters from Afghan prisons in mid-August. He said both ISIS and al-Qaida are recruiting from inside and outside Afghanistan.

“So certainly we should expect a resurgent ISIS. It would be very surprising if that weren’t the case,” he said, adding, “It remains to be seen that the Taliban are going to be able to take effective action against them.”

He called al-Qaida a more difficult problem for the Taliban because of their longstanding ties.

“So I think there are internal arguments inside the Taliban about the way forward,” he said. “What we would like to see from the Taliban would be a strong position against al-Qaida,” which they promised as part of the February 2020 Doha agreement that committed the United States to fully withdrawing from Afghanistan. “But I don’t believe that’s yet been fully realized.”

McKenzie declined to provide an estimate of the number of al-Qaida operatives inside Afghanistan.

“I think it’s probably slightly increased,” he said. “There’s a presence. We thought it was down pretty small, you know, toward the end of the conflict. I think some people have probably come back in. But it’s one of the things we look at, but I wouldn’t be confident giving you a number right now.”