A US Navy warship sailed within 12 nautical miles of an artificial island built up by China, US officials said on Wednesday, the first such challenge to Beijing under President Donald Trump.
The officials, speaking on condition of anonymity, said the USS Dewey was travelling close to the Mischief Reef in the Spratly Islands, among a string islets, reefs and shoals over which China has territorial disputes with its neighbours.
The so-called "freedom of navigation operation" comes at a time when Trump is seeking China's co-operation to rein in ally North Korea's nuclear and missile programs.
The move, the latest attempt to counter what Washington sees as Beijing's efforts to limit freedom of navigation in the strategic waters, is likely to anger China.
Under the previous administration, the US Navy conducted such voyages through the South China Sea.
The last such operation was carried out in October, approved by then-President Barack Obama.
China's extensive claims to the South China Sea, which sees about $5 trillion in ship-borne trade pass every year, are challenged by Brunei, Malaysia, the Philippines, Vietnam, as well as Taiwan.