The destroyer Lassen embarked early Tuesday morning on a five-hour patrol through hotly contested waters claimed by China and its neighbors that sparked headlines around the world and created a diplomatic firestorm in Beijing.
Lassen made a 72-nautical mile transit through the Spratly Islands, a collection of reefs, rocks and other natural features, past territorial claims made by Taiwan, Vietnam and China, according to two defense officials who spoke on background.
At various points in the patrol, Lassen was shadowed by Chinese vessels, including a frigate, a destroyer and an amphibious landing ship, officials said.
Chinese Nnaval activity peaked in the vicinity of Subi Reef, where U.S. officials and analysts have said China is building an airstrip capable of landing military aircraft. The Chinese destroyer was observed launching a helicopter, but officials described all maneuvers conducted by Chinese forces as "safe and professional."
The characterization of the Chinese behavior as professional is important, as other interactions between the U.S. and Chinese navies have been seen as more provocative in recent years.
In December 2013, the cruiser Cowpens nearly collided with a Chinese ship while China claims the Cowpens it was shadowing its new aircraft carrier during sea trials. And in August 2014, a Chinese fighter intercepted a Navy P-8A spy plane in the vicinity of China's Hainan Island and made close passes that Pentagon officials called "dangerous and unprofessional."
The Lassen is still operating operation in the vicinity of the Spratly Islands, though it's unclear when or if another patrol is imminent.
"It could be tonight, could be three weeks from now," an official said, adding that the Navy is hoping to make the patrols a routine part of operating in the region.
The Lassen's patrol set off a wave of official condemnations from China, which who had said for weeks preceding the patrol that the U.S. should avoid militarizing the dispute in the South China Sea by sending a warship through.
Media reports Tuesday said that Beijing was summoning the U.S. ambassador to lodge an official complaint.
Six nations in the region lay claim to parts or all of the Spratly Islands, a collection of reefs, rocks and other natural features. In the last two years, China has begun constructing islands on top of the reefs and claiming territorial seas around them to gain fishing and resource rights to most of the South China Sea.