Republican President Donald Trump questioned the integrity of the US election again on Tuesday, saying it would be “inappropriate” to take extra time to count the tens of millions of ballots cast by mail in his race against Democrat Joe Biden.

While Trump, who trails in national opinion polls, cast doubt on mail-in votes, Biden offered a message of unity in two rallies in the state of Georgia as part of a foray into traditional Republican territory with a week left to go before Election Day on November 3.

Early voting, both by mail and in person, topped 70 million on Tuesday, more than half of the total turnout in the 2016 election, according to the US Elections Project at the University of Florida.

Americans are rushing to cast ballots in record numbers as they look to avoid exposure to the coronavirus.

The huge volume of mail ballots — more than 46 million have already been cast — could take days or weeks to tally, experts say, meaning that a winner might not be declared the night of November 3, when polls close.

“It would be very, very proper and very nice if a winner were declared on November 3, instead of counting ballots for two weeks, which is totally inappropriate and I don’t believe that that’s by our laws,” Trump told reporters at the White House before leaving for campaign rallies in three states. “We’ll see what happens.”

Trump has repeatedly and without evidence suggested that an increase in mail voting will lead to an increase in 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.

Democratic officials, activists and voters have voiced deep anxieties that Trump will not accept the outcome if he loses. Biden has called it his biggest fear.

Democrats are voting early in greater numbers than Republicans this year, according to data from the Elections Project, but some states do not allow officials to begin counting those ballots until the polls close.

Republicans in a series of court battles across the US are trying to limit the time and opportunities voters have to send in ballots.