Trump continues to legally challenge Biden's victory

US President Donald Trump will continue on Tuesday with legal challenges to last week's election results after Attorney General William Barr ordered federal prosecutors to consider any 'substantial' allegations of voting process irregularities.

Barr's directive to prosecutors led to the resignation of the lead lawyer overseeing election fraud investigations. It came after days of attacks on the integrity of the election by Trump and his Republican allies, who have spread a narrative of voter fraud without providing evidence for such claims.

Trump has not conceded the election to Democrat Joe Biden, who secured more than the 270 Electoral College votes needed to win on Saturday.

Trump's campaign has filed several lawsuits alleging that the election results were flawed. Judges are reviewing lawsuits in Michigan and Georgia, while experts say Trump's legal efforts have little chance of changing the election outcome.

Barr said on Monday that 'unsubstantiated or far-fetched claims' should not be the basis for an investigation, and his letter does not state that the Justice Department has uncovered any voting irregularities that affected the outcome of the election.

But he said he was authorizing prosecutors to 'investigate substantial allegations' of voting and ballot counting irregularities.

Biden's campaign team claims that Barr is fueling Trump's far-fetched allegations of fraud.

Jessica Levinson, a professor at Loyola Law School in Los Angeles, said the latest lawsuit in Pennsylvania is unlikely to succeed because it 'sounds like a repeat of arguments that the Trump legal team has made in court and out of court'.

Trump's re-election team asked for patience on Monday to continue gathering evidence of alleged voter fraud.

Meanwhile, Biden, who has begun work on his transition to the White House, will give a speech on Monday to defend the Affordable Care Act, the landmark health care law known as Obamacare, as the US Supreme Court hears arguments in a lawsuit by the Trump administration seeking to overturn it. 

Trump and Republicans have repeatedly tried to repeal the 2010 law passed during the tenure of President Barack Obama, when Joe Biden was Vice President. 

As Biden begins the transition process, his team is considering legal action against a federal agency for delaying the certification of his victory over Trump.

The General Services Administration (GSA) typically publicly ascertains a presidential candidate so that the transfer of power can begin. However, this has not yet happened, and the law itself does not specify when the GSA should certify the president-elect. GSA Administrator Emily Murphy, whom Trump appointed in 2017, has not yet determined that the winner is 'apparent,' a spokeswoman for the agency said. 

A representative for Biden's team told reporters that the transition team would consider legal action if the GSA does not act according to the law, Reuters reported.