MANILA, Philippines — USS Charleston (LCS-18) was tracked by Chinese forces on Tuesday after the ship “illegally intruded” into the area surrounding a contested South China Sea maritime feature, according to Beijing.

Chinese forces were dispatched to monitor the Independence-class LCS near Sabina Shoal early Tuesday, the PLA said. China claims the maritime feature under its 10-Dash Line territorial assertion.

“The U.S. action infringes upon China’s sovereign rights and interests, jeopardizes maritime security, and is detrimental to regional peace and stability. The U.S. side should immediately cease such activities. Forces of the STC remain on high alert at all times to resolutely safeguard national sovereignty and security and uphold regional peace and stability,” the People’s Liberation Army Southern Theater Command said in a statement.

The PLA Navy, China Coast Guard cutters and China Maritime Militia vessels have maintained Beijing’s presence at Sabina Shoal since a 2024 standoff with Manila. These operations are sustained by a large forward-deployed Chinese force in the Spratly Islands, which is host to several reclaimed land bases with air fields, ports, sensors and anti-aircraft and anti-ship missile systems.

The U.S. sail comes amid a month of heightened tensions between China and the Philippines. Since the beginning of October, at least eight close encounters have occurred across the South China Sea and Luzon Strait between the two countries.

U.S. Navy warships and Coast Guard cutters usually deploy to the South China Sea for Freedom of Navigation Operations. Last year, USS Higgins (DDG-76) held a FONOP at Scarborough Shoal in the aftermath of a severe collision between a PLAN guided-missile destroyer and CCG patrol vessel that left two Chinese sailors dead.

Forward-deployed LCSs under U.S. 7th Fleet regularly patrol the South China Sea and drill with Southeast Asian states. In July and August, USS Santa Barbara (LCS-32) held consecutive maritime cooperative activities with Philippine, Japanese and Australian forces throughout the region. Navy P-8A Poseidon and Marine Corps MQ-9A Reapers also provide intelligence, surveillance and reconnaissance support during these sails.