CNN anchor Jake Tapper. CNN CNN anchor Jake Tapper issued perhaps the strongest condemnation yet of President Donald Trump's baseless claims of voter fraud on Tuesday.

Trump has insisted he lost the popular vote in November's election because of millions of illegal ballots he has said were cast for Democrat Hillary Clinton, though he has provided no evidence for his claim. The president repeated the falsehood during a meeting with members of Congress on Monday, drawing bipartisan criticism from lawmakers.

Tapper sharply rebuked Trump's claim on CNN's "The Lead" on Tuesday, calling it "a stunning allegation for which the White House is providing no evidence."

"And there is a reason they are providing no evidence — there is no evidence," Tapper said. "It is not true."

Reporters grilled Sean Spicer, the White House press secretary, with questions about Trump's allegation on Tuesday. Spicer attributed Trump's belief to "studies and information he has" but declined to provide specifics.

When asked whether Trump would investigate his claims of voter fraud, Spicer said "maybe we will," but he maintained Trump was "very comfortable with his win."

Tapper pounced on the comments: "If there were even a fraction of the voter fraud that President Trump is alleging, he would be derelict not to order a major investigation." He continued:

"It would likely require a vast conspiracy involving public officials all over the country, and would likely have had far-reaching impact in other contests, tainting races down the ballot, not just the presidential race. "If President Trump's beliefs are true, Republican leaders in Congress should be holding hearings and trumpeting this injustice every single day. His Justice Department, his Department of Homeland Security — all of them would need to crack down immediately. "Unless of course, it's not even remotely true. Which is, of course, the case."

Trump made his original claim of voter fraud in November, weeks after his Election Day victory, as late waves of provisional and absentee ballots built up Clinton's lead, which ultimately reached nearly 3 million votes. Trump won the election with a lead of 306 to 232 in the Electoral College.

The rate of voter fraud is less than 0.001%, according to a report from the Brennan Center for Justice.

Watch Tapper's segment below: