A group of top Republican senators are pushing for details about the beefed-up security around the Capitol complex, arguing police have failed to justify the enhanced measures following the Jan. 6 riot.

Five GOP senators, who each hold top committee spots, sent a letter on Friday to Yogananda Pittman, acting chief of the Capitol Police, saying they were "concerned" about recent security moves.

"Capitol Police has repeatedly failed to provide specific, credible threat intelligence to adequately justify the current Capitol security posture, which remains disproportionate to the available intelligence," the senators wrote, pointing to the presence of the National Guard and perimeter fencing.

The letter was signed by Sens. James Inhofe (Okla.), Richard Shelby (Ala.), Marco Rubio (Fla.), Rob Portman (Ohio) and Roy Blunt (Mo.), the top Republicans on the Armed Services, Appropriations, Intelligence, Homeland Security and Rules committees, respectively.

The letter is the latest in growing scrutiny from lawmakers about the increased security around the Capitol. The Pentagon announced this week it would extend the presence of nearly 2,300 National Guardsmen at the Capitol through May 23, roughly half of the 5,100 currently stationed there. The deployment was initially expected to end this week. 

Senate GOP Leader Mitch McConnell (Ky.) also railed against the National Guard presence and the fencing, saying it was "overdone."

"I'm extremely uncomfortable with the fact that my constituents can't come to the Capitol. With all this razor wire around the complex it reminds me of my last visit to Kabul," he told reporters Wednesday.

The Capitol Police and top security officials have previously indicated that they are worried the Capitol could be targeted when President Biden gives a joint address, something that hasn't yet been scheduled.

Pittman has also indicated that the Capitol's security needs to be revamped after Jan. 6, when a pro-Trump mob was able to breach the building. Police have suggested having "permanent fencing, and the availability of ready, back-up forces in close proximity to the Capitol."

The GOP senators said it was "entirely unclear" why the current fencing remains, adding it "sends a terrible message to American citizens, as well as to our allies and adversaries, and it is not a long-term security solution."

They also said there has been a "lack of evidence" from the Capitol Police for the department's request that the National Guard continue to maintain a presence around the complex through late May.

The GOP senators are requesting a meeting with Pittman and included several questions in their letter that they want answers to by March 19, including what intelligence the Capitol Police had ahead of Jan. 6, the justification for current fencing, what changes have been made within Capitol Police and if surveillance could replace the National Guard troops.

"We strongly believe that the future of a secure and open Capitol complex lies with internal reform, creative thinking, and improvements made by the Capitol Police, in conjunction with other federal and local civilian law enforcement agencies," they added.