House Oversight Chairman Trey Gowdy said Sunday "we will never know" whether the FBI had a sufficient amount of evidence to make a proper case to secure surveillance warrants used to spy on former Trump campaign aide Carter Page.

The Justice Department released more than 400 pages of top-secret documents late Saturday evening related to the 2016 application for the Foreign Intelligence Surveillance Act warrant taken out on Page, in addition to three renewal applications — much of which were redacted.

[Byron York: FISA warrant application supports Nunes memo]

"Here's what we will never know: We'll never know whether or not the FBI had enough without the dossier, the unvetted, DNC-funded dossier, because they included it and everyone who reads this FISA application sees the amount of reliance they placed on this product funded by Hillary Clinton's campaign and the DNC," Gowdy, R-S.C., said on "Fox News Sunday" after calling Page "more like Inspector Gadget then he is Jason Bourne or James Bond."

"The other thing I hope my fellow citizens will take note of is the FBI missed a really good opportunity to tell the judge exactly who paid for that," he added. Gowdy also complained about the FBI's roundabout way of avoiding disclosure to the FISA court that research that led to the dossier was funded in part by the Democratic National Committee and the Hillary Clinton campaign — as alleged in the House Intelligence Committee memo released earlier this year.

The FBI and the Justice Department relied heavily on the now-infamous "Trump dossier" authored by former British spy Christopher Steele in obtaining the FISA warrants on Page. Congressional Republicans, who have often cited the use of the dossier as misinformation used to improperly monitor Trump and his campaign during the months leading up to the 2016 presidential election, have clashed with the DOJ and FBI in recent months to obtain documents related to the Russia and Hillary Clinton email investigations.

Democrats argued that the released FISA documents showed federal officials took appropriate measures to investigate a suspicious target.

Trump on Sunday called on Republicans to " get tough now," while noting that the more than 400 pages of records are "ridiculously redacted" and arguing they show special counsel Robert Mueller's Russia investigation is a "witch hunt."