WASHINGTON, Nov. 23 (CNA) - President Donald Trump's campaign on Monday asked a federal appeals court to revive a long-shot challenge to Pennsylvania's election results, saying officials should be halted from declaring President-elect Joe Biden as the state's winner.

The campaign said a lower-court judge erred in dismissing the case outright, rather than review additional allegations the campaign had dropped from the case but wanted to restore.

It said it never got a chance to litigate its "serious and well-founded claims" that Democratic officials schemed to ensure Biden's victory by counting potentially tens of thousands of defective mail ballots.

Counties in Pennsylvania faced a Monday deadline for delivering election results to the state's top election official for certification, although some were expected to miss the target.

Under Pennsylvania law, the candidate who wins the popular vote in the state is awarded all of its 20 Electoral College votes. The Democratic former vice president received 81,000 more votes in Pennsylvania than Trump, a Republican.

The campaign is appealing part of a decision from the US District Court for the Middle District of Pennsylvania.

The lawsuit filed by Trump's campaign had alleged inconsistent treatment by county election officials of mail-in ballots.

US District Judge Matthew Brann, said in his ruling on Saturday that the case was based on "strained legal arguments" and that he had "no authority to take away the right to vote of even a single person, let alone millions of citizens."

Brann also denied the campaign's request to add claims to its lawsuit, including an allegation that its due-process rights were violated.

The Trump campaign's appeal is focused on the narrow question of whether Brann improperly refused to let them amend their lawsuit a second time.

Pennsylvania's secretary of state has until Tuesday afternoon to respond. If the campaign loses its appeal, it could ask the US Supreme Court to review the case.