Charles Krauthammer said President Donald Trump should "stop digging" when it comes to his claims that Trump Tower was illegally wiretapped by then-President Obama during the campaign. 

The syndicated columnist sat down with Tucker Carlson after the leaders of the House and Senate Intelligence Committees said Thursday they've seen no evidence of the surveillance.

Krauthammer said it's clear now that "there's not a person in Washington" who thinks Trump's claims are true and the president is risking his credibility by continuing to pursue it. 

"He seems to have a belief in conspiracy theories. This is, after all, a man who said Ted Cruz's father was involved in some way with Lee Harvey Oswald. That's 'Twilight Zone' stuff," he noted.

Trump made the explosive claims in a series of tweets on the morning of March 4. In an interview Wednesday, Carlson pressed Trump on why he made the claims without first obtaining evidence to back them up. 

Trump still claimed there is "a lot" of evidence, citing news reports and saying he was referring to broader surveillance in his tweets. 

Krauthammer pointed out that if there were real proof, Trump could get it easily by calling top justice and intelligence officials. 

He agreed with Carlson that there may have been "mishandling" of communications involving Americans and Russian officials under surveillance, but that Trump's claims are distracting from those issues.

Watch the full discussion above and check out Charles' take on Trump's new budget proposal. 

LOOK: Spicer Treated Like a Rock Star at Trump's Nashville Rally

Tucker Debates Dem Who Launched Website on Trump's Alleged Russia Ties

Krauthammer: Damage to Trump 'Incalculable' If House Kills Health Care Bill