Citing three anonymous sources “familiar with his private comments”, the news site Axios said Trump “has told confidants he’ll declare victory on Tuesday night if it looks like he’s ‘ahead’.

“That’s even if the electoral college outcome still hinges on large numbers of uncounted votes in key states like Pennsylvania,” the site said, adding: “Trump has privately talked through this scenario in some detail in the last few weeks, describing plans to walk up to a podium on election night and declare he has won.

“For this to happen, his allies expect he would need to either win or have commanding leads in Ohio, Florida, North Carolina, Texas, Iowa, Arizona and Georgia.”

According to FiveThirtyEight.com, Trump leads in Ohio, Texas and Iowa while Biden is up in Florida, North Carolina, Georgia and Arizona. The races are all exceptionally tight: the biggest lead in the FiveThirtyEight.com polling average is Biden by three points in Arizona, the smallest Trump by 0.2 in Ohio.

Under the coronavirus pandemic, early and mail-in voting has reached unprecedented levels, fuelling expectations of record turnout but also fears many states will take longer than usual to count their ballots.

Trump’s tactics, Axios said, will depend on continuing to claim without evidence ballots counted after election day are illegitimate and evidence of voter fraud. Vote counting after election day is a regular feature of US elections.

Many of Trump’s claims have focused on Pennsylvania, where the race is close but where votes counted after 3 November are expected to favour Joe Biden, the Democratic nominee who leads most national and battleground polls. Both candidates campaigned heavily in the state this weekend.

Democrats have long worried that Trump will declare victory early, aiming to sow uncertainty and legal battles over ballots and results. Some observers have called the tactic the “red mirage”, which former housing secretary Julián Castro said this week “sounds like a super villain, and it’s just as insidious”.

“On election night, there’s a real possibility that the data will show Republicans leading early, before all the votes are counted,” Castro said. “Then they can pretend something sinister’s going on when the counts change in Democrats’ favour.”

On Sunday, on CNN’s State of the Union, Biden adviser Anita Dunn said she thought the victor would be known some time on 4 November, the day after election day.

“A lot of the early states that are battleground states, especially in the Sunbelt, Florida, Georgia, North Carolina, are states that tend to get their votes counted on election night,” Dunn said. “I think we will get some sort of indicator what kind of night it’s going to be from those three states. We will see. Obviously, Pennsylvania, Michigan, Wisconsin may be slower.”

The Pennsylvania official in charge of elections, Secretary of State Kathy Boockvar, a Democrat, told NBC’s Meet the Press there could be 10 times as many mail-in ballots than in 2016 and added: “I expect that the overwhelming majority of ballots in Pennsylvania, that’s mail-in and absentee ballots, as well as in-person ballots, will be counted within a matter of days.”

Axios said the Trump campaign was bullish about key states including Texas, Nevada, North Carolina, Arizona and Wisconsin. On ABC’s This Week, Trump adviser Jason Miller claimed: “If you speak with many smart Democrats, they believe President Trump will be ahead on election night, probably getting 280 electoral [votes], somewhere in that range. And then they’re going to try to steal it back after the election.

“We believe that we’ll be over 290 electoral votes on election night. So no matter what they try to do, what kind of hijinks or law suits or whatever kind of nonsense they try to pull off, we’re still going to have enough electoral votes to get President Trump re-elected.”

Miller’s claim rested on the idea that all ballots must be counted on election day, a legal and political nonsense. Nonetheless, the Trump campaign communications director Tim Murtaugh told Axios: “When he wins, he’s going to say so.”

Trump’s final 2020 tour, which began on Sunday in Michigan, is aimed at holding states he won four years ago and shoring up support in traditional Republican strongholds, like North Carolina and Georgia. Biden was due to hold two drive-in meetings in Pennsylvania, one of a string of former Democratic bastions in the north-east which Trump won from Hillary Clinton by less than a point.

New polls showed Biden holding on to a lead in Pennsylvania. The New York Times and Siena College gave the Democrat a six-point edge, while the Washington Post and ABC showed a seven-point margin.