Donald Trump is to sign an executive order today to launch an investigation into voter fraud during the 2016 US election.

White House press secretary Sean Spicer said onboard Air Force One the President will sign the order in the Oval Office. He didn't give more details.

Mr Trump has repeatedly said he believes there was widespread voter fraud in the November election and that scores of people were on voter rolls in multiple states or after they died.

The President originally voiced the claims after winning the US election, tweeting: “In addition to winning the Electoral College in a landslide, I won the popular vote if you deduct the millions of people who voted illegally”.

The President has also said he believes many people illegally voted more than once and that "none" of those ballots were cast for him, and instead benefitted Hillary Clinton.

This contributed to him losing the popular vote, he has repeatedly claimed.

Speaking in a White House interview on Wednesday, Mr Trump said: “What's going on with voter fraud is horrible. That's number one. Number two, I would've won the popular vote if I was campaigning for the popular vote.”

Asked why he was launching an investigation into fraud despite no evidence of voter fraud having yet been found, and despite vote recounts in four states that showed no evidence of prevalent fraud, and despite Republican House Speaker Paul Ryan saying “I have seen no evidence” of fraud, Mr Trump said there was “a lot to look into”.

He said: “We're gonna launch an investigation to find out. And then the next time -- and I will say this, of those votes cast, none of 'em come to me. None of 'em come to me. They would all be for the other side. None of 'em come to me. But when you look at the people that are registered: dead, illegal and two states and some cases maybe three states -- we have a lot to look into.”

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There is no evidence on the record to support Mr Trump's claims.