President Donald Trump and Democratic rival Joe Biden on Monday traded barbs and exhorted last-minute voters to turn out as they stumped in battleground states on the campaign's final day, while Americans set early voting records.

In Fayetteville, North Carolina, during the first of five planned rallies across four states, the Republican Trump dismissed national opinion polls showing him losing the race and offered apocalyptic warnings about a Biden presidency.

"A vote for Biden is a vote to give control of government over to the globalists, communists, socialists, the wealthy liberal hypocrites who want to silence, censor, cancel and punish you," Trump said.

In Cleveland, Ohio, a toss-up state once seen as a lock for Trump, Biden returned to the main themes animating his campaign, vowing to heal the nation's wounds while attacking Trump's handling of the coronavirus pandemic.

"Tomorrow we have an opportunity to put an end to a presidency that's divided this nation," Biden said, calling Trump "weak" and a "disgrace."

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 national polls showing Biden with a broad 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.

Trump will also travel to Pennsylvania, Wisconsin and Michigan - all states that he won narrowly in 2016 but that polls show could swing back to Biden this year.

Biden, 77, will spend the rest of his day in Pennsylvania after his Ohio speech.

In a year upended by the coronavirus pandemic, early voting has surged to levels never before seen in US elections. A record-setting 96 million early votes have been cast either in-person or by mail, according to the US Elections Project.

The record-breaking number is equal to 70% of the entire voter turnout for the 2016 election and represents about 40% of all Americans who are legally eligible to vote.

That unprecedented level of early voting includes 60 million mail-in ballots that could take days or weeks to be counted in some states, meaning a winner might not be declared in the hours after polls close on Tuesday night.

Twitter said on Monday it would attach a warning label to any tweets, including those from candidates, that claim an election win before either state election officials or national news outlets do so.

In a sign of how volatile the election could be, buildings in several cities were boarded up, including around the White House and in New York City including the iconic Macy's flagship.

The famed shopping destination of Rodeo Drive in Beverly Hills will be closed down on Tuesday, police said.

The FBI was investigating an incident in Texas when a pro-Trump convoy of vehicles surrounded a tour bus carrying Biden campaign staff. The caravan, which Trump praised, prompted the Biden campaign to cancel at least two of its Texas events, as Democrats accused the president of encouraging supporters to engage in acts of intimidation.

'Voter Intimidation Is illegal'

Eight state attorneys general, representing Illinois, Michigan, Minnesota, Nevada, New Mexico, North Carolina, Pennsylvania and Wisconsin on Monday warned they would not tolerate voter intimidation.

"Voter intimidation is illegal in every state, whether it happens in person or from a car," North Carolina Attorney General Josh Stein said in a statement. "People who witness concerning behavior should immediately report it to law enforcement authorities."

Trump will wrap up his campaign in Grand Rapids, Michigan, the same place he concluded his 2016 presidential run.

Biden, running mate Kamala Harris and their spouses will spend most of Monday in Pennsylvania, splitting up to hit all four corners of a state that has become vital to the Democrats' hopes.

Biden will rally union members and African-American voters near Pittsburgh before being joined for an evening drive-in rally by singer Lady Gaga.

Former President Barack Obama, whom Biden served as vice president for eight years, will hold a get-out-the-vote rally in Atlanta on Monday before an evening rally in Miami.

Biden has finished his campaign on the offensive, traveling almost exclusively to states Trump won in 2016 and criticizing the president's response to the coronavirus pandemic.

Biden accuses Trump of giving up on fighting the pandemic, which has killed more than 230,000 Americans and cost millions of jobs. Polls show Americans trust Biden more than Trump to fight the virus.

Dr. Anthony Fauci, the top US infectious diseases expert, has said the first doses of an effective coronavirus vaccine will likely become available to some high-risk Americans in late December or early January.

Trump, who has often disagreed with Fauci publicly, suggested early on Monday he might fire him after the election.

"Elect me, and I'm going to hire Dr. Fauci, and we're going to fire Donald Trump," Biden said in Cleveland.

Trump Again Questions Process

Trump questioned the integrity of the US election, saying a vote count that stretched past Election Day on Tuesday would be a "terrible thing" and suggesting his lawyers might get involved.

"I don't think it's fair that we have to wait for a long period of time after the election," Trump told reporters. Some states, including battlegrounds Pennsylvania and Wisconsin, do not start processing mail-in votes until Election Day, slowing the process.

In a statement, the Trump campaign said it would fight any Democratic attempt to "subvert state deadlines for receiving and counting ballots."

In Cleveland, Biden told voters that Trump would not be able to stop them from exercising their rights.

"Presidents don't determine who gets to vote," he said. "Voters determine who is going to be the President."

Trump has repeatedly said without evidence that mail-in votes are prone to fraud, although election experts say that is rare in US elections. Mail voting is a long-standing feature of American elections, and about one in four ballots was cast that way in 2016.

Democrats have pushed mail-in voting as a safe way to cast a ballot, while Trump and Republicans are counting on a big Election Day in-person turnout.

Both campaigns have mobilized armies of lawyers in preparation for post-election litigation battles.

A federal judge in Texas on Monday was hearing a Republican request to throw out about 127,000 votes already cast at drive-through voting sites in the Democratic-leaning Houston area.