US President Joe Biden says a first summit in Washington with leaders from the Association of Southeast Asian Nations (ASEAN) marks the launch of a "new era" in the relationship between the United States and the 10-nation bloc.
In a joint 28-point "vision statement" after a two-day meeting, the two sides took what analysts called a symbolic step of committing to raise their relationship from a strategic partnership to a "comprehensive strategic partnership" in November.
On Ukraine, they reaffirm "respect for sovereignty, political independence, and territorial integrity", wording that goes further than past ASEAN statements. The statement does not condemn Russia by name for its February 24 invasion.
The summit marked the first time ASEAN leaders gathered as a group in Washington and their first meeting hosted by a US president since 2016.
Biden's administration hopes the effort will show the United States remains focused on the Indo-Pacific and the long-term challenge of China, which it views as its main competitor, despite Russia's invasion of Ukraine.
He also hopes to persuade ASEAN countries to toughen their stance on Russia's invasion of Ukraine.
Biden told the ASEAN leaders that "a great deal of history of our world in the next 50 years is going to be written in the ASEAN countries, and our relationship with you is the future, in the coming years and decades".
Biden called the US-ASEAN partnership "critical" and said: "We're launching a new era - a new era - in US-ASEAN relations."
Vice-President Kamala Harris said the United States would remain in Southeast Asia for "generations" and stressed the need to maintain freedom of the seas, which the United States says is challenged by China.
Neither she nor Biden mentioned China by name. The United States has accused China of using coercion against its neighbours.
Harris said Washington would continue to respond with ASEAN to the threat of COVID-19, having already donated more than 115 million vaccine doses to the region
She also said both sides needed to show collective ambition on climate change.
ASEAN includes Brunei, Cambodia, Indonesia, Laos, Malaysia, Myanmar, the Philippines, Singapore, Thailand and Vietnam. Myanmar's leader was excluded from the summit over a coup last year. The Philippines, in transition after an election, was represented by its foreign minister.
Biden hosted a summit dinner at the White House on Thursday, and his administration promised $US150 million ($A217 million) for areas including infrastructure, security, pandemic preparedness and clean energy.
Still, US spending pales in comparison with that of China, which in November alone pledged $US1.5 billion in development assistance for ASEAN to fight COVID-19 and fuel economic recovery.
Biden announced the nomination of Yohannes Abraham, chief of staff on his National Security Council, to be ambassador to ASEAN, filling a post vacant since the start of Donald Trump's administration in 2017.
ASEAN countries share many US concerns about China's assertiveness, including its claim of sovereignty over vast swaths of the South China Sea, where several have rival claims.
However, they remain cautious about siding more firmly with Washington, given their predominant economic ties with China and limited US economic incentives.