US President Barack Obama overnight tore into Donald Trump for sowing suspicion about the integrity of the US election, telling the Republican presidential nominee to "stop whining" and focus on winning votes.
Mr Obama called Mr Trump's intensifying, pre-emptive warnings about voter fraud "unprecedented" in modern politics.
The rhetoric is not based on any evidence, Mr Obama said, but is simply aimed at discrediting the election before the first votes are counted.
"You start whining before the game's even over?" Mr Obama said at a press conference. "Then you don't have what it takes to be in this job."
Mr Obama delivered his biting rebuke at White House, where he hosted Italy's Prime Minister Matteo Renzi for a state visit.
The president initially said he would pull his punches when it comes to politics, respecting the official setting. But when he was asked about Mr Trump's rhetoric, he did not hold back.
The president also accused Mr Trump of showering praise and modelling his policies on Russian President Vladimir Putin to a degree that is "unprecedented in American politics."