Two US Navy warships sailed near islands claimed by China in a bid to challenge Chinese efforts to limit freedom of navigation in the area, US officials said.
In a move likely to anger Beijing, the Higgins, a guided-missile destroyer, and the Antietam, a guided-missile cruiser, came within 12 nautical miles of the Paracel Islands in the South China Sea, the Daily Telegraph reports.
The ships carried out maneuvering operations near Tree, Lincoln, Triton and Woody islands in the Paracels, one of the officials said.
The archipelago is among a string of islets, reefs and shoals over which China has territorial disputes with its neighbours, and the operation was the latest attempt to counter what Washington sees as Beijing's efforts to limit freedom of navigation in the waters around them.
While the operation had been planned months in advance and similar operations have become routine, it comes at a particularly sensitive time and just days after the Pentagon uninvited China from a major US-hosted naval drill.
US President Donald Trump's cancellation of a summit with North Korean leader Kim Jong Un has put further strain on US-China ties amid a trade dispute between the world's two largest economies.
Critics of the "freedom of navigation" operations say they have little impact on Chinese behaviour and are largely symbolic.
Today's manoeuvre comes after a US Navy destroyer carried out a similar operation close to Mischief Reef in the Spratly Islands in March.
China's foreign and defence ministries did not immediately respond to requests for comment.
Pentagon officials have long complained that China has not been candid about its rapid military build-up in the region, and claim it is using the South China Sea islands to gather intelligence.
Satellite photographs taken on May 12 showed China appeared to have deployed truck-mounted surface-to-air missiles or anti-ship cruise missiles at Woody Island.
This month, China's air force landed H-6K bombers on disputed islands and reefs in the South China Sea as part of a training exercise in the region, triggering concern from Vietnam and the Philippines.
Chinese officials have accused Washington of viewing their country in suspicious, "Cold War" terms.
China's claims in the South China Sea, through which about US$5 trillion in shipborne trade passes each year, are contested by Brunei, Malaysia, the Philippines, Taiwan and Vietnam.
The United States has said it would like to see more international participation in freedom-of-navigation operations in the South China Sea.