Carl Bernstein claimed on Friday there is "serious belief" in the FBI and Congress that there is an "active cover-up" to stymie any investigation into the Trump campaign's ties to Russia.

Citing FBI and Capitol Hill sources, Bernstein said on CNN that there is no definitive evidence yet of criminal activity resulting in indictment.

"There is serious belief in the FBI and in the congressional committees of the House and the Senate, that there here is an active cover-up going on involving, trying to keep investigators from finding out what happened in terms of the Trump campaign and Trump associates, near the top of the campaign and what happened in their associations with Russians," Berstein said.

Multiple congressional panels, as well as the FBI, are conducting separate Russia inquiries.

He was sparring with former Trump aide Jason Miller about another ex-Trump adviser, Carter Page, who reportedly is suspected of working as a foreign operative for or colluded with the Russian government.

Miller blamed the media for leaning on stories with "baseless allegations" citing anonymous sources.

Bernstein, best known for his investigative reporting that shed light on the Watergate scandal leading to President Richard Nixon's resignation in 1974, defended the value of unnamed sources.

Though he said he didn't want to "belabor the example of Watergate," Bernstein said that "in Watergate, in the two years of stories we did at the Washington Post and also at the New York Times, there was not a single quoted source. It was all reporting based on anonymous sources."