TEHRAN, Iran — Iranian officials ratcheted up pressure Wednesday ahead of a weekend nuclear deadline for European nations to come up with a solution for Iran to sell its oil abroad in the aftermath of escalated U.S. sanctions.

President Hassan Rouhani reiterated a threat that Tehran would take additional steps away from the 2015 nuclear accord on Friday and accelerate nuclear activities if Europe fails to provide a solution, calling it Iran's third, "most important step" away from the deal.

"Iran's third step is of an extraordinarily significant nature," Rouhani said, without detailing what it would entail, but saying a "decree will be announced today or tomorrow."

Meanwhile, Iran's Foreign Ministry announced that seven members of the 23-member crew of the seized British-flagged oil tanker Stena Impero held in the Persian Gulf would be released — an apparent good-will gesture meant to defuse tensions.

Iran seized the tanker on July, saying it violated Iranian laws, after authorities in the British territory of Gibraltar seized an Iranian tanker said to be to be carrying fuel to Syria in violation of EU sanctions on oil sales to Damascus.

The Iranian vessel — the Adrian Darya 1, formerly known as the Grace 1 — was released earlier this month and set sail for eastern Mediterranean. It turned off its tracking beacon off the coast of Syria this week, leading to renewed speculation that its oil will end up there, despite earlier assurances to the contrary.

Iranian President Hassan Rouhani speaks at a session of parliament to debate his proposed tourism and education ministers, in Tehran on Tuesday (Vahid Salemi/AP)
Iranian President Hassan Rouhani speaks at a session of parliament to debate his proposed tourism and education ministers, in Tehran on Tuesday (Vahid Salemi/AP)

Both Rouhani and Deputy Foreign Minister Abbas Araghchi expressed doubts Europe would succeed in salvaging the nuclear deal between Tehran and world powers.

U.S. sanctions imposed after President Donald Trump withdrew America from the deal have curbed Iran’s oil exports and sent its economy into free fall while what was left of the deal steadily unraveled.

French officials said the U.S. has a pivotal role in the European bid to get Iran to comply, notably that Washington issue waivers for specific oil deals, according to French officials.

Foreign Minister Jean-Yves Le Drian told reporters Tuesday that Trump must “obligatorily issue waivers on this or that point” for major trading partners such as China.

Tensions have spiked across the Persian Gulf over mysterious tanker explosions, the shooting down of a U.S. military surveillance drone by Iran and America deploying more troops and warplanes to the region.

Under the nuclear agreement, Iran agreed to limit its enrichment of uranium in exchange for the lifting of economic sanctions. But since Trump’s pullout, Iran has already taken steps contrary to the terms of the deal although it insisted they remained within the framework of the deal.

The International Atomic Energy Agency confirmed last week that Iran’s stockpile of low-enriched uranium still exceeds the amount allowed by the deal. The U.N. agency also said Iran continues to enrich uranium up to 4.5 percent, above the 3.67 percent allowed under the deal but still far below weapons-grade levels of 90 percent.

French President Emmanuel Macron is leading talks seeking relief for Iran and de-escalation of tensions. This week, Foreign Minister Mohammad Javad Zarif flew to Moscow while Araghchi went to Paris and elsewhere in Europe to press for a solution.

Little seems to have come out of those trips.

"I see that it's unlikely a conclusion will be reached with Europe today or tomorrow," Rouhani said.

Araghchi was quoted by the official IRNA news agency as saying "it is unlikely European countries can take an effective step" before the deadline.

Meanwhile, the idea of a phased credit line to pre-purchase Iranian oil has been floated amid the diplomatic efforts, something Araghchi reiterated.

Europe, he said, needs to compensate Iran in the "amount of $15 billion over a 4-month span" and "after that, Iran is ready for talks."

Rouhani indicated that after Friday's deadline expires and Iran takes the next step, another two-month deadline to Europe will follow with the aim to resume talks.

"They know what we want, and we know what they want," Rouhani said.

Later on Wednesday, Foreign Ministry spokesman Abbas Mousavi told state TV that while judicial procedure on the British-flagged oil tanker is still underway, the captain of the ship has been asked — under Iran's "humane policy" — to let seven of the crew return to their country.

He said the captain decided seven crew members from India would be the ones to leave.

Erik Hanell, CEO of the Swedish shipping group Stena Bulk that owns the Stena Impero, said it wasn’t immediately clear when the seven would be freed. The remaining 16 crew members are to stay on board the vessel.

"Their ordeal may soon be over, and they may return to their families, however, we cautiously await official confirmation of their release date," Hannell said, adding the announcement was "a positive step on the way to the release of all the remaining crew, which has always been our primary concern and focus."

An oil tanker is on fire in the sea of Oman on June 13. A series of attacks on oil tankers near the Persian Gulf has ratcheted up tensions between the U.S. and Iran -- and raised fears over the safety of one of Asia’s most vital energy trade routes, where about a fifth of the world’s oil passes through its narrowest at the Strait of Hormuz. . (ISNA/AP)
An oil tanker is on fire in the sea of Oman on June 13. A series of attacks on oil tankers near the Persian Gulf has ratcheted up tensions between the U.S. and Iran -- and raised fears over the safety of one of Asia’s most vital energy trade routes, where about a fifth of the world’s oil passes through its narrowest at the Strait of Hormuz. . (ISNA/AP)

Associated Press writers Jan M. Olsen in Copenhagen and Elaine Ganley in Paris contributed to this report.