US president Donald Trump says he will leave the White House if Joe Biden is formally confirmed as the next US president by the electoral college.
Biden leads Trump by 306 votes to 232 under the electoral college system used to pick US presidents.
The tally is far more than the 270 needed to win, and Biden also leads the popular vote by more than six million.
Electors will meet next month to formalise the vote, with Democrat Joe Biden due to be sworn in as president on 20 January.
The president and his supporters have lodged a number of legal challenges over the election, but most have been dismissed.
Earlier this week, Trump finally agreed to allow the formal transition to President-elect Biden’s team to begin, following several weeks of uncertainty.
The decision means Biden is able to receive top security briefings and access key government officials and millions of dollars in funds as he prepares to take over on 20 January.
The normally routine process of transitioning from one president to another and confirming the result has been derailed by President Trump’s refusal to concede.
Under the US electoral system, voters do not directly choose the next president. Instead, they vote for 538 officials, who are allocated to American states based on their population size.
Biden has already announced his choice of top officials for when he takes over from Donald Trump in January and said that co-operation from the White House over the transition had been “sincere”.