U.S. President Donald Trump and Democratic rival Joe Biden made a last-ditch push for votes in battleground states on Monday as their campaigns prepared for post-election disputes that could prolong a divisive presidential election.

Trump, who is trailing in national opinion polls, has continued to lob unfounded attacks at mail-in ballots, suggesting he would deploy lawyers if states are still counting votes after Election Day on Tuesday. His deputy campaign manager, Justin Clark, said the campaign would fight any Democratic attempt to "subvert state deadlines for receiving and counting ballots."

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At a rally in Scranton, Pennsylvania, Trump warned that state plans to count mail ballots that arrive up to three days after Election Day amounted to a "dangerous situation."

The U.S. Supreme Court last month denied a Republican challenge to that policy but could still revisit the dispute after the election.

Biden campaign manager Jennifer O'Malley Dillon reminded reporters on Monday that states routinely needed time after election night to finish counting votes in past U.S. elections.

"Under no scenario will Donald Trump be declared a victor on election night," she said.

The election has prompted an unprecedented wave of litigation over whether to adjust voting rules in light of the COVID-19 pandemic.

Both sides have amassed armies of lawyers who are prepared to take on post-election battles.

On Monday, a federal judge in Texas rejected a Republican bid to throw out about 127,000 votes already cast at drive-through voting sites in the Democratic-leaning Houston area.

Trump has spent the final days of the campaign predicting victory and deriding Biden for backing restrictions that aim to slow the spread of the coronavirus.

"A vote for Biden is a vote for lockdown, misery and layoffs," he told the crowd in Scranton.

In Pittsburgh, Biden told supporters that the country's future rested in their hands.

"When America votes, America is heard. And when America is heard, the message will be out loud and clear: It's time for Donald Trump to pack his bags and go home," he said.

Trump, 74, is seeking to avoid becoming the first incumbent president to lose re-election since fellow Republican George H.W. Bush in 1992. Despite Biden's national polling lead, the race in swing states is seen as close enough that Trump could still piece together the 270 votes needed to prevail in the state-by-state electoral college system that determines the winner.