US President Donald Trump has said he no longer opposes government aid for Joe Biden's transition team in his closest statement yet to finally conceding he lost the presidential election.

Mr Trump's tweet that the General Services Administration should "do what needs to be done" came after the agency's head Emily Murphy said she was releasing the long-delayed assistance.

President Trump has spent the last three weeks since the 3 November election claiming without any evidence that Mr Biden's convincing victory was the result of fraud.

Ms Murphy, who denies acting under political pressure, has refused until now to release the standard package of aid that her agency manages to Biden's incoming team.

Politicians and business executives have put pressure on the little-known federal agency to recognise the election results and free up millions of dollars in federal funds, office space and briefings for Mr Biden's team.

The GSA had said Ms Murphy, who was appointed to her job by Donald Trump in 2017, would "ascertain" or formally approve, the transition when the winner was clear.

"Contrary to media reports and insinuations, my decision was not made out of fear or favoritism," Ms Murphy wrote.

The Presidential Transition Act of 1963 provides no firm deadline for the GSA to act, but the agency has historically acted once media organisations call a winner, which happened on 7 November.

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Biden certified as the winner in Michigan

Michigan has certified Mr Biden as the winner of the state's US election poll - giving the Democratic US president-elect a further 16 electoral college votes.

The Board of State Canvessers voted three to one in his favour after he topped Mr Trump by nearly 156,000 votes out of the 5.5 million cast.

The certification is likely put to an end efforts by Mr Trump to overturn the result in Michigan, one of the key states he needed to capture to win re-election.

However, the US President's legal team later said it would continue to challenge the results of the 2020 presidential election.

"Certification by state officials is simply a procedural step," said Jenna Ellis, a legal adviser to Mr Trump's 2020 campaign, in a statement.

Without providing any evidence to back up her claim, she added: "We are going to continue combatting election fraud around the country as we fight to count all the legal votes. Americans must be assured that the final results are fair and legitimate."

Mr Biden had earlier announced a foreign policy and national security team crammed with veterans from the Barack Obama years, signalling an end to the upheaval under Mr Trump and a return to traditional US diplomacy.

It included Irish-American Jake Sullivan as national security adviser - he previously advised Mr Biden when he was vice president under Mr Obama.

Former state department number two Antony Blinken will be the new US secretary of state.

Mr Biden also named the first female head of intelligence, the first Latino chief of Homeland Security and a heavyweight on climate issues - Obama-era top diplomat John Kerry.

As Mr Trump continued to make flailing attempts at overturning the results of the election three weeks ago, Mr Biden's roll out of Cabinet names was his biggest step yet signalling he is ready to change the US's direction on 20 January.

The list put out by the Democrat's team ahead of a formal announcement tomorrow demonstrated a push to bring back the US role of leader in multilateral alliances, in contrast to Mr Trump's "America first" regime.

"They will rally the world to take on our challenges like no other - challenges that no one nation can face alone," Mr Biden tweeted. "It's time to restore American leadership."

Mr Blinken will spearhead a fast-paced dismantling of Mr Trump's go-it-alone policies, including rejoining the Paris climate agreement and the World Health Organization and resurrecting the Obama-crafted Iran nuclear deal.

Mr Biden named the first woman, Avril Haines, as director of national intelligence, and Cuban-born Alejandro Mayorkas to head the Department of Homeland Security, the agency whose policing of tough immigration restrictions under Mr Trump was a frequent source of controversy.

Signalling the Democratic president-elect's campaign promise to raise the profile of global warming threats, he named John Kerry as a new special envoy on climate issues.

And in a further message of US re-engagement with the international community, Mr Biden named career diplomat Linda Thomas-Greenfield for UN ambassador.

The picks underline an emphasis on professionals whom Mr Biden already knows well, in contrast to the Trump White House where officials were often picked without having traditional background for the job or proved incompatible and departed in acrimony.

With their long job histories in senior government positions, the incoming team will also have the advantage of ready made relationships both in Washington and on the international stage.