“They’ll go out and they’ll vote and they’re going to have to go and check their vote by going to the poll and voting that way, because if it tabulates then they won’t be able to do that. So, let them send it in and let them go vote,” the president said in an interview in North Carolina.
“And if their system’s as good as they say it is, then obviously they won’t be able to vote. If it isn’t tabulated, they’ll be able to vote. So that’s the way it is, and that’s what they should do,” he told WECT-TV at Wilmington airport.
He made a similar appeal to supporters at the airport: “You can’t let them take your vote away.
“These people are playing dirty politics — dirty politics. So if you have an absentee ballot or, as I call it, a solicited ballot… you send it in, but I would check it, in any event, I would go and follow it and go vote.”
It came on a day Mr Trump sped through a VJ Day speech, trumpeting American strength and squeezing in a swipe at Democratic rival Joe Biden.
He stood before a famous Second World War battleship to declare the port city of Wilmington a “Heritage City”. He pointed to a bolt of lightning and said it was God saluting the event.
He honoured war veterans including 97-year-old Hershel “Woody” Williams, the sole surviving marine from the war to receive the Medal of Honour after he served in the Battle of Iwo Jima in the Pacific.
“He’s 100% sharp,” Mr Trump said of Mr Williams, who had travelled to the key battleground state with the president aboard Air Force One.
“I know a 78-year-old who’s not so sharp,” the president added, a clear allusion to Mr Biden.
White House press secretary Kayleigh McEnany had insisted earlier this week that there was no “political purpose” to the visit to North Carolina, but the president lost no time in criticising Mr Biden.
“This is the most important election in the history of our country. I really believe that, because we’re running against people that have got some big issues,” he told supporters on the airport tarmac. “They have got some big, big problems. They’re stone cold crazy.”
He won North Carolina by 3.6 percentage points in 2016, but polls are showing an extremely close race taking shape in a state that generates 15 electoral votes for the winner.