The mainstream media is trying to "diminish" the president's claims that Justice Department (DOJ) Inspector General (IG) Michael Horowitz's upcoming report on alleged FISA abuse will be "historic," former Chairman of the House Oversight Committee and Fox News Contributor Jason Chaffetz said Saturday.

Appearing on "Fox & Friends: Weekend" with hosts Pete Hegseth, Ed Henry, and Rachel Campos-Duffy, Chaffetz said that it is no coincidence that after the president's exclusive interview on "Fox & Friends" Friday, "less than eight hours later New York Times and Washington Post almost simultaneously within the hour come out with a story trying to diminish what the president was saying."

TRUMP ON 'FOX & FRIENDS': HOUSE DEMS 'LOOKED LIKE FOOLS' THIS WEEK, UPCOMING FISA REPORT WILL BE 'HISTORIC'

"The Inspector General has now -- if the report is correct -- will be making his fourth referral to the Department of Justice for potential criminal prosecution or inter-agency disciplinary action," Chaffetz explained. "That means the Director of the FBI, the Deputy Director of the FBI, the Deputy Assistant Director of the FBI, and now counsel within the FBI would be recommended for potential criminal prosecution or disciplinary action."

"That is as serious as it gets," he told the "Friends: Weekend" hosts.

For more than a year-and-a-half, Horowitz has been investigating alleged misconduct related to the FISA warrants delivered by the Foreign Intelligence Surveillance Court (FISC). The Justice Department and FBI obtained warrants in 2016 to surveil Trump adviser Carter Page. It is unclear, at this point, if Page was the only Trump official that the DOJ obtained a FISA warrant against.

That highly anticipated report will likely spark new congressional investigations and deliver critical information to other federal reviews probing allegations of abuse by the Justice Department and the FBI.

Horowitz has been probing how the infamous and salacious anti-Trump dossier compiled by former British spy Christopher Steele was used to secure the original FISA warrant for Page in October 2016, as well as three renewals.

Horowitz also has looked into why the FBI may have regarded Steele – funded by the Hillary Clinton campaign through law firm Perkins Coie – a credible source, and why the bureau used news reports to bolster Steele’s credibility before the FISA court.

"This is not some low-level person. You have to have the highest level of security at the DOJ in order to be involved in this," said Chaffetz. "This article tried to diminish him as some low-level person who, you know, probably went rogue. But, that's the person that they used and doctoring the documentation to spy on a presidential campaign -- that's pretty serious."

Echoing the president, Chaffetz said the IG report is "just the precursor" to U.S. Attorney John Durham's report -- which has reportedly now shifted into a criminal probe.

Fox News' Brooke Singman contributed to this report.

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Senate Judiciary Committee Chairman Lindsey Graham, R-S.C., told Fox News Wednesday that Horowitz's report is set to be released on Dec. 9.