WASHINGTON • President Donald Trump's campaign has taken another step in its long-shot legal strategy to overturn his election defeat with a Michigan lawsuit, while Georgia announced a recount and President-elect Joe Biden worked on laying the foundation of his administration.

Mr Biden will name long-time aide Ron Klain as his White House chief of staff, according to the New York Times.

Mr Trump's team went to the federal court on Wednesday to try to block Michigan, a Midwestern battleground state that he won in 2016 but lost to Mr Biden, from certifying the Nov 3 election results.

Mr Trump trailed in the state by roughly 148,000 votes, or 2.6 percentage points, according to Edison Research, with nearly 100 per cent of the vote counted. The lawsuit made allegations of voting misconduct, with the focus on the Democratic stronghold of Wayne County, which includes Detroit.

Mr Jake Rollow, a spokesman for the Michigan Department of State, said the Trump campaign was promoting false claims to erode public confidence in the election.

"It does not change the truth: Michigan's elections were conducted fairly, securely, transparently, and the results are an accurate reflection of the will of the people," Mr Rollow said in a statement.

Mr Biden last Saturday clinched victory as he won a series of battleground states to exceed the 270 electoral votes needed in the state-by-state Electoral College that determines who wins the presidency.

He also was winning the national popular vote by more than 5 million votes, with a few states still counting ballots.

Judges have tossed out several of the Trump lawsuits, and legal experts say the litigation has scant chance of changing the outcome.

Mr Biden widened his lead on Wednesday in key states as vote-counting continued, including Pennsylvania where he now holds a 50,000-vote lead.

REUTERS