CIA Director John Brennan

CIA Director John Brennan Carolyn Kaster/AP

Will the Senate Push John Brennan to Resign From the CIA?

Calls for Brennan's head began Thursday evening after the spy agency admitted it had hacked into Senate computers.

Democratic Sens. Mark Udall and Martin Heinrich both called for CIA Director John Brennan's resignation late Thursday after the spy agency admitted it had improperly hacked into Senate staffers' computers used during a review of the agency's Bush-era interrogation practices.

"After being briefed on the CIA Inspector General report today, I have no choice but to call for the resignation of CIA Director John Brennan," Udall said in a statement. "The CIA unconstitutionally spied on Congress by hacking into Senate Intelligence Committee computers."

Additional reports claimed that Republican Sen. Lindsey Graham was also asking Brennan to step down due to the controversy. An aide Thursday denied knowing of any call for resignation.

Senate Majority Leader Harry Reid stopped short of calling for Brennan's head, but said the CIA's admission was "appalling and deeply threatening to our system of checks and balances."

"The CIA's leadership must take action to address these misdeeds, restore its trust with Congress and ensure that this episode will never, ever be repeated," Reid added.

Other senators, including Senate Intelligence Committee Chairwoman Dianne Feinstein, have refused comment on whether they believe Brennan should be removed from his post. Sen. Saxby Chambliss, the Intelligence panel's top Republican, said calls for a resignation were "premature."

"There are still a lot of undisclosed facts out there," Chambliss said.

Sen. Susan Collins said she had "been shown no evidence that [Brennan] directed, authorized, or approved of the intrusions themselves, which I consider to be a very serious infringement on Congressional oversight."

Earlier Thursday, the CIA admitted that its employees had "acted in a manner inconsistent with the common understanding" agreed to between the agency and its Senate overseers, according to CIA spokesman Dean Boyd. The mea culpa marked a sharp reversal of previous denials by Brennan, who said allegations of hacking of Senate computers was "beyond the scope of reason."

Feinstein earlier this year took to the Senate floor to deliver bombshell allegations that the CIA had secretly accessed her panel's computers that were being used to review documents related to the government's torture, detention, and rendition policies allowed during George W. Bush's presidency. She accused the CIA of impeding her staffers' investigation and charged the agency with possibly violating the Constitution.

Udall, who serves on the Intelligence panel, was the first senator to state publicly that Brennan should give up his position. The Colorado Democrat is facing reelection this year in a tight race that The Cook Political Report has deemed a Toss-Up.