China's Southern Theater Command blasted the USS Charleston for breaching Chinese territorial waters around Sabina Shoal on Tuesday, labeling the incursion a violation of its sovereignty.
Chinese warships were dispatched to the area to monitor the U.S. vessel's movements, the command said, citing the need to safeguard national security.
Sabina Shoal sits amid the Spratly Islands, a chain of reefs and atolls claimed by China, the Philippines and other regional actors; the Philippines, a U.S. defense partner, has long disputed Chinese claims.
The U.S. Navy has not yet issued a statement on the incident, leaving the dispute in limbo while Beijing signals it will seek diplomatic redress.
China has lodged a formal protest with Washington and is preparing a statement for the international community, underscoring the high stakes of freedom of navigation operations in the South China Sea.