White House press secretary Sean Spicer on Tuesday confirmed that President Donald Trump believes millions of people voted illegally in November’s election, despite a total absence of evidence to support this view.

“The president does believe that. He has stated that before. I think he’s stated his concerns of voter fraud and people voting illegally during the campaign and continues to maintain that belief based on studies and evidence that people have presented to him,” Spicer told reporters at the daily press briefing.

Pressed for evidence to support the claim, Spicer said only, “I think the president has believed that for a while, based on studies and information he has.” He did not say what those studies or information were.

During the course of the press conference, Spicer grew visibly frustrated at the repeated questions about Trump’s false claim. “He believes what he believes based on the information he was provided,” Spicer told CNN’s Jeff Zeleny. Asked what Trump’s belief means for American democracy, Spicer snapped, “It means I have answered your question.”

Spicer also struggled to explain why Trump had not prioritized an investigation into the issue, which NPR’s Mara Liasson said would be “a scandal of astronomical proportions,” if it were actually true.

“Maybe we will. We’ll see where we go from here,” Spicer said.

Trump surprised congressional leaders Monday night at the White House when he claimed that he would have won the popular vote, were it not for “3 to 5 million illegals” who voted for Hillary Clinton, according to sources who spoke to The Huffington Post.

Trump won the presidency with a majority of the Electoral College, though Clinton won nearly 3 million more popular votes than Trump did. Ever since, Trump has seemed obsessed with the topic of whether he was legitimately elected.

These concerns were amplified by intelligence community reports of Russian efforts to influence the U.S. presidential election. After months of denying these reports, Trump said earlier this month, “I think it was Russia.” Minutes later, he said other countries could have done it, too.