US Democratic challenger Joe Biden has said he will reverse President Donald Trump’s move to withdraw from the World Health Organization (WHO) “on day one” if he wins November’s election.
Mr Trump formally began the pull out on Tuesday after signalling the move in May. He said the WHO was under China’s control during the coronavirus crisis.
The process could take at least a year. Mr Trump currently trails Mr Biden in the race for president by a margin of more than 10 percentage points.
Analysts have urged caution in interpreting the polls, but Mr Biden’s lead is far greater than that of Mr Trump’s 2016 opponent Hillary Clinton at the same point in the campaign.
Many voters are concerned by the administration’s handling the pandemic and its economic fallout.
There have been almost three million confirmed cases of the virus in the US and more than 130,000 deaths, far more than in any other country. Meanwhile, tens of millions have lost their jobs.
In a tweet on Tuesday evening, Mr Biden said the US was better off working within the international community on global health issues.
“Americans are safer when America is engaged in strengthening global health,” he said.
“On my first day as President, I will rejoin the @WHO and restore our leadership on the world stage.”
Democrats in Congress confirmed that the legislature had been notified of the president’s decision.