China and the Philippines have had repeated confrontations in the waters over the past year, including around a warship, grounded in 1999 by Manila on the contested Second Thomas Shoal, which hosts a garrison.

Both countries said on Monday that their coast guard ships had collided near the disputed Sabina Shoal, located 140 kilometres (86 miles) west of the Philippine island of Palawan and about 1,200 kilometres from Hainan island, the closest Chinese landmass.

China claims almost the entire South China Sea despite an international tribunal ruling that its assertion has no legal basis.

The United States condemned the "dangerous actions" against "lawful Philippine maritime operations" on Monday after the latest clash.

"These actions are the latest examples of (China) using dangerous and escalatory measures to enforce its expansive and unlawful South China Sea maritime claims," State Department spokesman Vedant Patel said.

Asked about Patel's remarks on Tuesday, his Chinese counterpart Mao Ning defended Beijing's "legal measures to safeguard its territorial sovereignty and maritime rights and interests".

"The US is not a party in the South China Sea and has no right to intervene in maritime disputes between China and the Philippines," Mao told a regular briefing. 

"The US should stop provoking confrontation in the South China Sea, not disrupt regional stability and not escalate tensions," Mao said.

Analysts have said Beijing's aim is to push eastwards from the Second Thomas Shoal towards the neighbouring Sabina Shoal in the Spratly Islands, encroaching on Manila's exclusive economic zone and normalising Chinese control of the area.

The confrontations have echoes of 2012 when Beijing took control of Scarborough Shoal, another strategic feature in the South China Sea closest to the Philippines.