The USS Stethem sailed close to Paracel Islands archipelago, claimed by China and others.
China responded by sending military vessels and fighter jets to the area.
It happened hours before US President Donald Trump and Chinese counterpart Xi Jinping spoke on the phone.
During the call, Mr Xi told Mr Trump that « negative factors » were affecting US-China relations, according to a read-out of the call carried on Chinese state TV.
A White House statement about their call did not say if they had discussed the incident. It said the leaders had instead « reaffirmed their commitment to a denuclearised Korean peninsula ».The US has repeatedly warned China against its occupation and aggressive reclamation of islands in disputed waters, but Beijing says it is within its sovereign rights to do so.
What happened near Triton Island?In a statement late on Sunday, China’s foreign ministry confirmed reports that the USS Stethem had entered waters claimed by China.
The warship had sailed within 12 nautical miles of Triton Island – which is also claimed by Taiwan and Vietnam – as part of its « freedom of navigation » operations, according to news agencies and Fox News citing US defence officials.
UN rules dictate that any territory can claim the waters up to 12 nautical miles from its coast. The sailing of a US ship within those limits indicates the US does not recognise the territorial claim.