A day after President Donald Trump accused former President Barack Obama of wiretapping his communications during the late stages of the 2016 presidential campaign, White House press secretary Sean Spicer said Sunday that neither Trump nor any White House official will be commenting further on the matter.

Citing unspecified “reports concerning potentially politically motivated investigations,” Spicer announced in a statement that “neither the White House nor the President will comment further” until Congress investigates the explosive allegation as part of its existing probe into Russia’s interference in the election.

Of course, it was Trump himself who claimed, in a bizarre series of tweets Saturday morning, that his predecessor had wiretapped his communications during the campaign. It is unclear whether Trump was referring to specific intelligence he’d received in his capacity as president, or whether he was simply referring to an article from the far-right website Breitbart News that ran Friday, claiming that Obama “sought, and eventually obtained, authorization to eavesdrop on the Trump campaign.”

“Terrible!” Trump tweeted on Saturday. “Just found out that Obama had my ‘wires tapped’ in Trump Tower just before the victory. Nothing found. This is McCarthyism!”

Spicer’s statement on Sunday suggests the White House doesn’t plan to offer any evidence supporting the president’s politically charged claim.

A spokesman for Obama denied that the former president, or any other White House official, had ordered surveillance on a private U.S. citizen.

“Any suggestion otherwise is simply false,” Kevin Lewis said Saturday.

During an appearance Sunday on ABC’s “This Week,” White House deputy press secretary Sarah Sanders said that Trump “is going off of information that he’s saying has led him to believe that this is a very real potential.” Yet she, too, did not offer evidence to back up the president’s claim.

“If this happened,” Sanders said, “this is the biggest overreach and the biggest scandal.”