Speaking on Wednesday at a virtual East Asia Summit attended by Chinese Premier Li Keqiang, Biden said Washington would start talk with partners in the Indo-Pacific about developing a regional economic framework, something critics say his regional strategy has lacked.

Southeast Asia has become a strategic battleground between the United States and China, which controls most of the South China Sea, and Beijing has turned up military and political pressure on fiercely democratic Taiwan, a self-ruled island Beijing considers its own.

Biden reiterated the US had a "rock-solid" commitment to Taiwan.

"We are deeply concerned by China's coercive ... actions," Biden said, charging that they "threaten regional peace and stability."

Li Keqiang told the summit, which brought together leaders of the 10-nation Association of Southeast Asian Nations with regional partners, that upholding peace, stability, freedom of navigation and overflight in the South China Sea was in everyone's interest.

"The South China Sea is our common home," he said.

Biden last week said the US, which is obliged by a 1979 law to provide Taiwan with the means to defend itself, would come to Taiwan's defence if it was attacked by China.

Those comments caused a stir because they appeared to depart from a long-held US policy of "strategic ambiguity" as to how Washington would respond to such a scenario.

The White House said Biden was not signalling a change in US policy toward Taiwan, and some analysts dismissed his comments as a gaffe.

Tensions between Taiwan and China have escalated in recent weeks as Beijing has staged repeated air missions over the Taiwan Strait, the waterway separating the island and the mainland.

China expressed displeasure at Biden's comments last week, urging Washington "not to send the wrong signals to the forces of Taiwan independence, to avoid seriously harming Sino-US ties and peace and stability in the Taiwan Strait."

Biden joined Southeast Asian leaders in rebuking Myanmar's junta.

"In Myanmar, we must address the tragedy caused by the military coup which is increasingly undermining regional stability," he said, calling for the release of political prisoners and a return to democracy.

ASEAN began three days of summits on Tuesday without a representative from Myanmar following its top general's exclusion for ignoring peace proposals.

Biden also said he would speak out for "human rights in Xinjiang and Tibet (and) the rights of the people of Hong Kong".

China denies rights abuses in its outlying regions of Xinjiang and Tibet and in the former British colony of Hong Kong.

Australian Associated Press