BEIJING: Beijing on Friday criticised the United States, Japan and the Philippines and defended its actions in the South China Sea as "lawful" after US President Joe Biden hosted a trilateral summit in Washington.

"China firmly opposes the relevant countries manipulating bloc politics, and firmly opposes any behaviour that provokes or lays plans for opposition, and hurts other countries' strategic security and interests," foreign ministry spokeswoman Mao Ning said.

President Biden on Thursday pledged to defend the Philippines from any attack in the South China Sea.

The summit at the White House came amid repeated confrontations between Chinese and Philippine vessels in the disputed waterway that have raised fears of wider conflict.

"We firmly oppose engaging in closed cliques that exclude others in the region," Mao told a regular press conference.

"Japan and the Philippines can of course develop normal relations with other countries, but they should not invite factional opposition into the region, much less engage in trilateral cooperation at the cost of hurting another country's interests.

"If these are not wanton smears and attacks on China, what are they?" she said.

Beijing claims almost the entirety of the South China Sea, brushing aside competing claims from several Southeast Asian nations including the Philippines.

"China's actions in the East China Sea and South China Sea are appropriate and lawful, and beyond reproach," Mao added.

 - AFP