By Steve Holland and Trevor Hunnicutt

OPA-LOCKA, Fla./WILMINGTON, Del. (Reuters) – U.S. President Donald Trump hunts for support in four battleground states on Monday while Democratic rival Joe Biden focuses on Pennsylvania and Ohio during the final day of campaigning in their race for the White House.

The Republican Trump trails Biden in national opinion polls ahead of Tuesday’s Election Day. But 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 that determines the winner.

Trump, aiming to avoid becoming the first incumbent president to lose re-election since fellow Republican George H.W. Bush in 1992, will hold five rallies on Monday in North Carolina, Pennsylvania, Wisconsin and Michigan.

He won those states in 2016 against Democrat Hillary Clinton, but polls show Biden is threatening to recapture all four for Democrats.

In a year that has seen much of American life upended by the coronavirus pandemic, early voting has surged to levels never before seen in U.S. elections. A record-setting 94 million early votes have been cast either in-person or by mail, according to the U.S. Elections Project, representing about 40% of all Americans who are legally eligible to vote.

Trump will wrap up his campaign in Grand Rapids, Michigan, the same place he concluded his 2016 presidential run with a post-midnight rally on Election Day.

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 former vice president’s hopes.

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

He also will make a detour to bordering Ohio, spending time on his final campaign day in a state that was once considered a lock for Trump, who won it in 2016, but where polls now show a close contest.

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 closing out the campaign in the evening with a rally in Miami.

Biden has wrapped up the campaign on the offensive, traveling almost exclusively to states that Trump won in 2016 and criticizing the president’s response to the coronavirus pandemic, which has dominated the race.

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.

During a frantic five-state swing on Sunday, Trump – who was impeached by the Democratic-led House of Representatives last December and acquitted by the Republican-controlled Senate in February – claimed he had momentum.

He promised an economic revival and imminent delivery of a vaccine to fight the pandemic.

Dr. Anthony Fauci, the top U.S. 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 as director of the National Institute of Allergy and Infectious Diseases after the election.

A ‘TERRIBLE THING’

Trump again questioned the integrity of the U.S. election, saying a vote count that stretched past Election Day would be a “terrible thing” and suggesting his lawyers might get involved.

Americans have already cast nearly 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.

“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.

Trump has repeatedly said without evidence that mail-in votes are prone to fraud, although election experts say that is rare in U.S. 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 in the coronavirus pandemic, while Trump and Republicans are counting on a big Election Day in-person turnout.

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

“We’re going in the night of – as soon as the election is over – we’re going in with our lawyers,” Trump told reporters without offering further explanation.

The attorneys general of Michigan and Pennsylvania, both Democrats, challenged Trump’s rhetoric on Twitter.

“The election ends when all the votes are counted. Not when the polls close,” Michigan Attorney General Dana Nessel wrote.

In a sign of how volatile the election could be, buildings for blocks around the White House were boarded up over the weekend. Federal authorities planned to extend the perimeter fencing around the White House to by several blocks, encompassing the same area fenced out during this summer’s protests against racism and police brutality, according to U.S. media.

To help ensure mail-in ballots are delivered in a timely fashion, a U.S. judge on Sunday ordered the U.S. Postal Service to remind senior managers they must follow its “extraordinary measures” policy and use its Express Mail Network to expedite ballots.

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

The FBI, meanwhile, is 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.

(Reporting by Steve Holland in Opa-Locka, Florida, and Trevor Hunnicutt in Wilmington, Delaware; Writing by John Whitesides; Editing by Scott Malone and Alistair Bell)