A US Navy guided-missile destroyer performed a so-called Freedom of Navigation operation (FONOP) near disputed Scarborough Shoal in the South China Sea on Wednesday, just two days after two Chinese military vessels collided while chasing a Philippine Coast Guard ship in nearby waters.

MANILA, Philippines (AP) — The U.S. deployed two warships Wednesday in a disputed South China Sea shoal where two Chinese ships collided earlier in the week while trying to drive away a smaller Philippine ship in a high-seas accident that raised alarms about maritime safety.

The Philippines expressed serious concern on Tuesday over what it called "dangerous manoeuvres and unlawful interference" by Chinese vessels during a coast guard supply mission for Filipino fishermen in the Scarborough Shoal in the South China Sea.