Image copyright Getty Images Image caption "We will probably never know" if the Democratic candidate won the popular vote, said Kris Kobach (L)

The man leading President Donald Trump's commission on voter fraud has stoked unproven claims that millions voted illegally for Hillary Clinton.

"We will probably never know" if the Democratic candidate won by more than three million votes, said Kris Kobach, the panel's chairman.

Mr Trump attended the body's first meeting on Wednesday, pledging his strong support.

Last year's results were certified by the Federal Election Commission.

Democrats suspect the Presidential Advisory Commission on Election Integrity, which the president established in May, is a ploy to suppress left-leaning voters.

But Mr Trump told the council on Wednesday: "Every time voter fraud occurs, it cancels out the vote of a lawful citizen, and undermines democracy."

"Can't let that happen."

Is there any evidence?

Unsubstantiated claim was started by self-styled conservative voter fraud specialist Greg Phillips, who tweeted: "Number of non-citizen votes exceeds 3 million"

His tweets were picked up by right-wing fringe websites such as Infowars.com

Fact-checking website Snopes.com says there is "zero evidence" that "illegal aliens" voted in election

"Don't buy it," says Politifact, which points to research suggesting there have been 56 cases of non-citizens voting numbers between 2000-2011

A Pew study in 2012 found millions of invalid voter registrations because people moved or died, but "zero evidence" of fraud

Mr Trump won the all-important electoral college vote in November 2016 by prevailing in Midwestern states, however, Mrs Clinton gathered more ballots nationwide - known as the popular vote.

The Republican president has insisted he in fact won the popular vote, "if you deduct the millions of people who voted illegally", without offering any evidence for the claim.

State election officials have disputed Mr Trump's claim, and at least 20 states have refused to comply with the committee's request to provide them with information for all 200 million registered US voters, including their names, addresses, political affiliation and voting history.

The commission is led by two Republicans, prompting fears from opponents it is a partisan exercise that could lead to new ID requirements and other measures making it harder to vote.

Mr Kobach told NBC on Wednesday: "I think the President-elect is absolutely correct when he says the number of illegal votes cast exceeds the popular vote margin between him and Hillary Clinton.

"Let's suppose that the commission determined that there were a certain number of votes cast by ineligible voters - you still won't know whether these people who were ineligible voted for Trump or for Clinton or for somebody else," added Mr Kobach, who is Kansas' secretary of state.

"And so it's impossible to ever know exactly if you took out all the ineligible votes what the final tally would be in that election."

Mr Kobach, an advocate of tougher laws on immigration and voter identification, has been dubbed the "king of voter suppression" by the American Civil Liberties Union's voting rights project.

Kentucky Secretary of State Alison Lundergan Grimes, who has refused to submit voter records to the White House commission, said in a statement that her state "will not aid a commotion that is at best a waste of taxpayer money and at worst an attempt to legitimise voter suppression efforts across the country".