President Donald Trump has signed an executive order today establishing a commission to review alleged voter fraud and voter suppression in the American election system.

Vice President Mike Pence and Kansas Secretary of State Kris Kobach were announced today as the Chair and Vice Chair of the bipartisan "Presidential Commission on Election Integrity."

"The commission will review policies and practices that enhance or undermine the American people's confidence in the integrity of federal elections and provide the president with a report that identifies system vulnerabilities that lead to improper registrations and voting," Deputy press secretary Sarah Huckabee Sanders said today in announcing the executive order.

President Trump tells ABC News' David Muir alleged voter fraud probe has 'a lot to look into'

In the aftermath of the 2016 election, Trump claimed widespread voter fraud explained why former Secretary of State Hillary Clinton emerged with nearly 3 million more popular votes. To date, neither Trump nor his team has provided evidence to substantiate the claims, but they have promised an investigation.

“You can never really find, you know, there are going to be -- no matter what numbers we come up with there are going to be lots of people that did things that we're not going to find out about,” Trump told ABC News' David Muir in January. "But we will find out because we need a better system where that can't happen."

Membership of the commission is still taking shape but so far already includes Indiana Secretary of State Connie Lawson (R), New Hampshire Secretary of State Bill Gardner (D), Maine Secretary of State Matthew Dunlap (D), former Ohio Secretary of State Ken Blackwell (R) and the commissioner of the election assistance commission Christie McCormick.

The commission's report on its findings is expected sometime in 2018, Sanders said.

“The experts and officials on this commission will follow the facts where they lead, meetings and hearings will be open to the public for comments and input and we will share those updates as we have them,” Sanders said.

The announcement is the latest indication that the president intends to pursue action, as promised, on his controversial and so-far unsubstantiated assertion that "millions" of people illegally cast ballots in the 2016 presidential election.

The president first raised the issue in a tweet in late November of 2016 claiming it resulted in his loss in the popular vote by nearly 3 million votes.

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 — Donald J. Trump (@realDonaldTrump) November 27, 2016

Shortly after his inauguration Trump said he would be "asking for a major investigation into voter fraud," and the White House teased the potential for Trump to sign an executive order establishing a commission.

I will be asking for a major investigation into VOTER FRAUD, including those registered to vote in two states, those who are illegal and.... — Donald J. Trump (@realDonaldTrump) January 25, 2017

An ABC News fact-check in January 2017 found the claim about massive widespread voter fraud was disputed by election officials across the country. After contacting officials in all 50 states to ask for the number of voter fraud instances in the 2016 election, the 20 states that responded all said voter fraud was not widespread. Most said “very” or “extremely” rare. In 3 of the country’s 4 most populated states (ie. California, New York and Florida), election officials say they found zero cases of voter fraud this past election. And a study published this month by the Brennan Center for Justice at the NYU School of Law found that 40 in 42 jurisdictions researchers studied, there were no known incidents of non citizens voting in 2016.

The appointment of Kobach to the commission is also likely to raise questions. Kobach is a controversial figure for his crusade against voter fraud in the state of Kansas, as well as his role in assisting states in crafting legislation to crackdown on illegal immigration. He also was an architect of the National Security Entry-Exit Registration System following the September 11 attacks, which was widely criticized by human rights groups for targeting Muslim immigrants.

In April, Kobach announced he had obtained his first conviction of a non-U.S. citizen who illegally voted in a Kansas election.

ABC News' Lauren Pearle contributed to this report.