By Trevor Hunnicutt and Alexandra Alper

WILMINGTON, Del./WASHINGTON (Reuters) – President Donald Trump and Democratic challenger Joe Biden will barnstorm across battleground states in the American Midwest where the coronavirus pandemic has exploded again, as they head into the final weekend before Election Day on Tuesday.

Trump will hold rallies on Friday in Michigan, Wisconsin and Minnesota, while Biden has planned stops in Wisconsin and Minnesota as well as Iowa on his busiest day of campaigning during the general election race.

Michigan and Wisconsin were two of the three historically Democratic industrial states, along with Pennsylvania, that narrowly voted for the Republican Trump in 2016, delivering him an upset victory. Minnesota, which has not voted for a Republican presidential candidate since 1972, is one of the few Democratic states that Trump is trying to flip this year.

Biden, running mate Kamala Harris and both of their spouses will spend their final day of campaigning on Monday in Pennsylvania, enabling them to hit all four corners of that closely divided state in the race’s final hours, the campaign said.

Trump has trailed Biden in national opinion polls for months, partly because of widespread disapproval of his handling of the coronavirus. Opinion polls in the most competitive states that will decide the election have shown a closer race.

The pandemic and an extraordinary level of enthusiasm have prompted Americans to vote early in unprecedented numbers.

More than 82 million votes have been cast either by mail or in person, nearly 60% of the total number of votes in the entire 2016 election, according to the U.S. Elections Project at the University of Florida.

The deluge of mail-in ballots makes it likely that the winner of several states, including major battlegrounds such as Pennsylvania and Wisconsin, will not be clear on Tuesday night. Election officials expect vote-tallying to take days.

On Thursday, a federal appeals court barred Minnesota election officials from implementing a plan to count ballots arriving up to a week after Election Day as long as they were postmarked by next Tuesday.

Trump has repeatedly claimed without evidence that mail-in ballots are susceptible to fraud, and has more recently argued that only the results available on election night should count.

Early voting data show that far more Democrats have voted by mail, while Republicans are expected to turn out in greater numbers on Tuesday.

This means preliminary results from states like Pennsylvania that do not begin counting mail-in ballots until Election Day could show Trump in the lead before flipping as more Democratic-heavy ballots are added, a phenomenon some have called the “red mirage” and the “blue shift.” Several Pennsylvania counties have said they will not begin counting mail-in ballots until Wednesday.

CLASHING OVER PANDEMIC

The pandemic has dominated the final days of the campaign. The coronavirus has killed nearly 229,000 people in the United States and hammered the economy.

Since overcoming his own COVID-19 infection, Trump has maintained a frenetic pace, holding up to three rallies a day with thousands of attendees despite concerns the events could spread the virus. Biden has held smaller events, including “drive-in” rallies where supporters remain in their cars for safety.

Trump has for months played down the pandemic, telling supporters in recent weeks that the country is “turning the corner” even as cases surge.

The president’s oldest son also tried to minimize the crisis, telling Fox News on Thursday the pandemic has “gone to almost nothing.” He spoke on the same day that more than 1,000 people died of COVID-19 in the United States and the country reported a single-day record of more than 91,000 cases.

“The number is almost nothing because we’ve gotten control of this thing. We understand how it works. They have the therapeutics to be able to deal with this,” Donald Trump Jr. said on Laura Ingraham’s program.

Biden has sharply criticized Trump’s approach to the virus.

“Donald Trump has waved the white flag, abandoned our families and surrendered to this virus,” Biden said in Tampa, Florida, on Thursday.

(Additional reporting by John Whitesides in Washington and Joseph Ax in Princeton, New Jersey; Editing by Scott Malone and Howard Goller)