President Trump arrives to meet with business leaders in the White House on Jan. 23. (Matt McClain/The Washington Post)

President Trump plans to sign an executive order Thursday afternoon related to voter fraud, his press secretary told reporters without providing additional details.

A day earlier, Trump called for a “major investigation into VOTER FRAUD” in back-to-back tweets that said such a probe would cover “those registered to vote in two states, those who are illegal” and “those registered to vote who are dead (and many for a long time).” For weeks, Trump has claimed that he lost the popular vote in November's election because there were millions of illegal votes cast for Democratic rival Hillary Clinton. Trump insisted during a private reception with congressional leaders Monday that there were 3 million to 5 million ballots illegally cast, allowing Clinton to win the popular vote by more than 2.8 million votes, although she lost the electoral college vote to Trump.

The president and his aides have yet to provide any verifiable facts to back up his claim, and analyses of the election found virtually no confirmed cases of voter fraud, let alone millions of fraudulent votes. The National Association of Secretaries of State, which represents many of the country's state elections officials, said in a statement Tuesday that it is “not aware of any evidence that supports the voter fraud claims made by President Trump.” Trump's campaign attorneys fought recount attempts in several states by Green Party candidate Jill Stein and stated in a recent court filing, “All available evidence suggests that the 2016 general election was not tainted by fraud or mistake.”

Trump reiterated his call for an investigation during an interview with ABC News that aired Wednesday night. In defending himself, the president lashed out at the author of a 2012 Pew Center study that Trump and his team have pointed to as evidence of widespread fraud, even though the study showed no such thing. Trump said that despite what fellow Republicans and experts might say on the matter, “millions” of his supporters agree with him.

“We're going to launch an investigation to find out,” Trump said. “And I will say this. Of those votes cast, none of them come to me. None of them come to me. They would all be for the other side. None of them 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.”