China's military said on Wednesday it monitored and "drove away" a US destroyer that sailed near the disputed Scarborough Shoal in the strategic busy waterway of the South China Sea.
The first known US military operation in at least six years within the shoal's waters came a day after the Philippines accused Chinese vessels of "dangerous maneuvers and unlawful interference" during a supply mission around the atoll.
In a statement, the Chinese military's Southern Theater Command said the USS Higgins had entered the waters "without approval of the Chinese government" on Wednesday.
"The US move seriously violated China's sovereignty and security, severely undermined peace and stability in the South China Sea," it added, vowing to keep a "high alert at all times".
The US Indo-Pacific Command declined to comment, referring questions to the US Navy's 7th Fleet, which did not immediately respond. The US embassy in Beijing, the Chinese capital, also offered no immediate comment.
China claims almost the entire South China Sea, despite overlapping claims by Brunei, Indonesia, Malaysia, the Philippines, Taiwan and Vietnam.
The United States regularly carries out "freedom of navigation" operations in the South China Sea, challenging what it says are curbs on passage imposed by China and other claimants.
The Scarborough Shoal has been a major source of tension in the South China Sea, a conduit for more than $3 trillion of annual ship-borne commerce.
The actions of Chinese vessels in the shoal this week also resulted in a collision of two of them, Manila said, the first such known in the area.
China's coast guard said it had taken "necessary measures" to expel Philippine vessels from the waters.
In 2016, an international arbitral tribunal ruled there was no basis in international law for Beijing's claims, based on its historic maps. China does not recognize that decision, however.
