Philadelphia (CNN) House Oversight Committee Chairman Jason Chaffetz said Wednesday he doesn't "see any evidence" of voter fraud, and his committee won't investigate it.

Earlier in the day, President Donald Trump said he wanted to launch an investigation, after claiming -- without evidence -- between 3 to 5 million fraudulent votes had been cast in the 2016 election, costing him the popular vote. Trump could sign an executive order or presidential memorandum initiating a Justice Department-led investigation into voter fraud as early as Thursday, a senior administration official told CNN.

"I will be asking for a major investigation into VOTER FRAUD, including those registered to vote in two states, those who are illegal and ... even, those registered to vote who are dead (and many for a long time). Depending on results, we will strengthen up voting procedures!" Trump wrote in two consecutive tweets Wednesday morning.

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

even, those registered to vote who are dead (and many for a long time). Depending on results, we will strengthen up voting procedures! — Donald J. Trump (@realDonaldTrump) January 25, 2017

Chaffetz said Trump can use Justice Department employees to investigate the issue if he wants, but he's not interested in launching a congressional investigation.

"On the voter fraud issue, that really happens at the county level. I don't see any evidence," he told reporters at the congressional Republican retreat in Philadelphia. "But the President has 100,000 people at the Department of Justice and if he wants to have an investigation, have at it. I just don't see any evidence of it."

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