Fox host Tucker Carlson says he's gained access to previously unreleased Jan. 6 security video

House GOP leaders appear to have given a Fox News host exclusive access to more than 40-thousand hours of previously unreleased surveillance camera footage from the Jan. 6 riot at the U.S. Capitol.

After Axios reported on Monday that House Speaker Kevin McCarthy had authorized the release, Fox host Tucker Carlson said on his program Monday night that he had gained "unfettered" access to the video, saying that some of his "smartest producers" have been reviewing the footage at an undisclosed location for about a week.

It was unclear on Tuesday where Carlson's team was reviewing the footage, or exactly who they got it from, and McCarthy's office did not immediately respond to an ABC News request for comment.

Fox News refused to comment beyond referring to what Carlson said on his program.

On Monday, Carlson claimed that some of the footage appears to contradict "the story that we've been told for more than two years," but he was short on details or specifics. Instead, Carlson teased that his team's findings would air on his program next week.

Carlson has repeatedly spread conspiracy theories about the circumstances surrounding the Jan. 6 attack on the Capitol and has suggested it was part of a "false flag" operation to target Trump supporters.

The apparent offer to Carlson's team also comes as a recent filing from the voting company Dominion in their lawsuit against Fox News revealed damning internal communications showing top Fox personalities, including Carlson, expressing concerns the accuracy of false allegations of voter fraud even as they pushed to their audiences the false narrative of the 2020 election being stolen.

The U.S. Capitol Police maintain access to and control over such surveillance videos, but ABC News has learned that the department did not directly provide the videos to Fox.

"When Congressional Leadership or Congressional Oversight Committees ask for things like this, we must give it to them," U.S. Capitol Police Chief Tom Manger said in a statement to ABC News.

The Justice Department has already made public hundreds of hours of surveillance and body camera footage as part of their more than 900 prosecutions of rioters charged in the attack on the Capitol.

But at times, the DOJ has joined with the Capitol Police in expressing concern over the release of some footage that could disclose sensitive areas in the Capitol, the location of closed circuit cameras, and other sensitive security movements.

Separately, a coalition of media outlets, including ABC News, has also fought in court for the release of exhibits from those prosecutions, in many cases over the objections of defendants.

The possible release by House GOP leaders comes as Democratic leaders in the House say they are looking into the matter and brand the footage's release as having "potential national security implications."

"The apparent transfer of video footage represents an egregious security breach that endangers the hardworking women and men of the United States Capitol Police," House Democratic Leader Hakeem Jeffries wrote in a letter to his caucus on Tuesday.

The Jan. 6 House select committee had access to the footage but was careful in its decision-making about what particular clips they made public, sources on the committee said, given security concerns and the potential for sensitive operational information of the U.S. Capitol the videos could reveal.

The former chairman of the committee, Bennie Thompson, emphasized the potential security risks of irresponsibly releasing the videos and demanded an explanation from House Republicans as to why they would grant a Fox News host access to the trove of material.

"If Speaker McCarthy has indeed granted Tucker Carlson … and his producers access to this sensitive footage, he owes the American people an explanation," read a statement from former Jan. 6 committee chair Bennie Thompson, D-Miss., in part.

Rep. Jamie Raskin, D-Md, who also sat on the Jan. 6 committee, called Carlson a "pro-Putin" journalist and branded the release of the footage "an ethical collapse" in a tweet Monday.

"What security precautions were taken to keep this from becoming a roadmap for 2024 insurrection?" Raskin tweeted.

McCarthy appears to be less worried than some congressional lawmakers about security. He has been vocal about opening the Capitol building to public visitors following the COVID-19 pandemic and Jan. 6 riot.

And within minutes of Republicans taking the House majority in January, he directed magnetometers removed from entrances to the House floor, overturning former Speaker Pelosi's directive for lawmakers to go through such a security screening.

McCarthy also told reporters that he did not want fencing placed around the Capitol when President Joe Biden delivered his State of Union address earlier this month, saying he did not see a need for it.

The speaker has repeatedly called for congressional oversight into the Jan. 6 committee's investigation, even asking the body to preserve its records weeks before it disbanded at the end of the 117th Congress.

The bipartisan committee released and previewed numerous clips from security cameras on the day of the riots during its public hearings last year.

Still, McCarthy has signaled that Republicans in the current 118th Congress would release additional footage during hearings of their own.

ABC News' Luke Barr and Lauren Peller contributed to this report.