WASHINGTON- Donald Trump has accepted a formal US transition should begin for President-elect Joe Biden to take office.
The president said the federal agency overseeing the handover must "do what needs to be done", even as he vowed to keep contesting his election defeat.
The General Services Administration (GSA) said it was acknowledging Mr Biden as the "apparent winner".
It came as Mr Biden's victory in the state of Michigan was officially certified, a major blow to Mr Trump.
The GSA announcement means the president-elect now has access to top security briefings, office space and government officials as he prepares to take office on 20 January.
His transition website has now changed to a US government domain. He will begin announcing the people he wants in the top jobs in his cabinet on Tuesday.
It welcomed the start of the transition process as the Democratic president-elect gears up to be sworn in.
"Today's decision is a needed step to begin tackling the challenges facing our nation, including getting the pandemic under control and our economy back on track," a team statement said.
Earlier, Mr Biden unveiled his nominations for his foreign policy and national security team, consisting of old colleagues from his years in the Obama administration.
He is set to appoint Anthony Blinken as secretary of state and John Kerry as climate envoy, while Janet Yellen is tipped to be the first female US treasury secretary.
The list of selections came ahead of a formal announcement Tuesday. Most of the appointments will require Senate confirmation. (BBC)