A judge in Pennsylvania has dismissed a lawsuit from the Trump campaign that aimed to invalidate millions of mail-in votes in the state.

State judge Matthew Brann said the suit was "without merit", with Joe Biden having a lead of more than 80,000 in the state.

It comes amid a host of legal battles launched by the Trump camp with the president seeking to leverage the power of the Oval Office in an extraordinary attempt to block President-elect Joe Biden's victory.

President Donald Trump's legal team said on Saturday that his campaign has requested a recount of votes in the Georgia presidential race after results showed Democrat Joe Biden winning the state.

READ MORE: The extraordinary legal move attempted by Donald Trump to subvert Joe Biden election win

Republican secretary of state Brad Raffensperger on Friday certified the state's election results, which had Mr Biden beating Mr Trump by 12,670 votes out of about 5 million cast, or 0.25%.

Republican governor Brian Kemp then certified the state's slate of 16 presidential electors.

The statement from the president's legal team said: "Today, the Trump campaign filed a petition for recount in Georgia. We are focused on ensuring that every aspect of Georgia State Law and the US Constitution are followed so that every legal vote is counted.

"President Trump and his campaign continue to insist on an honest recount in Georgia, which has to include signature matching and other vital safeguards."

The statement added: "Without signature matching, this recount would be a sham and again allow for illegal votes to be counted. If there is no signature matching, this would be as phony as the initial vote count and recount.

"Let's stop giving the People false results. There must be a time when we stop counting illegal ballots. Hopefully it is coming soon."

Georgia law allows a candidate to request a recount if the margin is less than 0.5%. The recount would be done using scanners that read and tabulate the votes.

County election workers have already done a complete hand recount of all the votes cast in the presidential race. But that stemmed from a mandatory audit requirement and is not considered an official recount under the law.

State law requires that one race be audited by hand to ensure that the machines counted the ballots accurately, and Mr Raffensperger selected the presidential race.

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Because of the tight margin in that race, a full hand count of ballots was necessary to complete the audit, he said.

Mr Trump has criticised the audit, calling it a "joke" in a tweet that claimed without evidence that "thousands of fraudulent votes have been found".

Twitter has flagged the post as containing disputed information.