WASHINGTON _ President Donald Trump will sign an executive order Thursday detailing the nature of the investigation he has promised into his claim of widespread voter fraud, the White House said.
Trump was still working with senior advisers on the details of the order, which would address potential voter fraud and faulty registration, Press Secretary Sean Spicer told reporters.
In an interview with ABC News on Wednesday, Trump once again said, without offering evidence, that "millions of votes" were cast illegally in the election, including ballots cast in the name of dead voters, by noncitizens and by individuals registered in multiple states.
"There are millions of votes, in my opinion," he said, citing a Pew report as evidence when challenged.
The report's author recently reiterated its conclusion that voter rolls are susceptible to fraud but not that any widespread fraud has occurred.
Trump also said he wasn't concerned that he was undermining a core tenet of American government by raising doubts about the credibility of elections.
"Millions of people agree with me," he said.
Trump will sign the order in Washington after a trip to Philadelphia to speak with House and Senate Republicans, the White House said.
GOP lawmakers have been circumspect about whether they believe an investigation is necessary.
"If the administration decides to pursue some sort of investigation on that, we will certainly cooperate in any way that they ask for," Sen. John Thune (R-S.D.), chairman of the Senate Republican conference, told reporters at the retreat.
"But all I can tell you is this _ we had an election, it was a decisive outcome. We have a new president, a new Congress and I view the election as history and we're ready to roll up our sleeves and go to work for the American people."
Advocates have expressed concern that the investigation will be used as a way to limit voters' ability to cast ballots.
