Top Republican Mitch McConnell has said there will definitely be a peaceful transfer of power if Joe Biden wins the presidential election.

"Of course," McConnell responded to questions from reporters in Kentucky, where he sits as a senator.

"We've had a peaceful transfer of power going back to 1792, every four years, we've moved on to a new administration."

McConnell's comments follow mixed messages from Donald Trump, however. The president initially refused to commit to such a handover earlier this year, then last month said he would support a smooth transition.

"Peaceful transfer ... I absolutely want that, but ideally, I don't want a transfer because I want to win," Trump said at the time.

Since 3 November he has repeatedly accused Democrats of trying to "steal" the election, without offering evidence, and vowed to challenge vote counts in key states.