The Director of the CIA reacted furiously on Tuesday to a call by Sen. Ron Wyden (D-Ore.) to apologize for agents’ spying on Senate Intelligence Committee (SSCI) staffers in January 2014, during the staffers’ compilation of a report on Bush administration torture programs.

John Brennan struggled to compose himself in response to Wyden’s request in a hearing before the committee, taking exception to both the subject matter of the inquiry and its reference to espionage. He scowled at the senator throughout the exchange.

“This is the annual threat assessment, is it not?” Brennan asked rhetorically at the onset of his response, referring to the fact that the hearing was on an unrelated matter.

Brennan eventually said he had already apologized to committee leaders “about thede minimis access and inappropriate access that CIA officers made to five emails or so of senate staffers during that investigation.”

“But do not say that we spied on Senate computers or files,” he fumed. “We did not do that. We were fulfilling our responsibilities”

Brennan also accused Wyden of mischaracterizing two internal CIA investigations of the incident—one carried out by the CIA inspector general, and another conducted by a review board convened on Brennan’s orders.

Although the former was far more lenient in its assessment of CIA actions, Wyden refused to back down.

“I’d like to read the exact words,” the senator replied, referring to page 24 of an unclassified version of the review board’s findings. “It ‘resulted inappropriate access to SSCI work product.’ And your inspector general reached the same conclusion.”

“When you’re talking about spying on a committee responsible for overseeing your agency, in my view, that undermines the very checks and balances that protect our democracy and it’s unacceptable in a free society,” Wyden added.

Brennan then said that he disagreed with the lawmaker’s understanding of how the situation unfolded, claiming that the CIA was actually victimized first by prying eyes.

“Do you not agree there was improper access that senate staffers had to CIA internal deliberative documents?” Brennan asked. “Was that not inappropriate or unauthorized?”

Although witnesses at congressional hearings aren’t supposed to be allowed to ask questions, Wyden retorted that, as far as he knew, SSCI staffers had appropriately conducted themselves.

“But I asked about CIA conduct in two reviews,” he noted. “The inspector general and your review board said it was improper.”

“Yes,” Brennan responded, “and I am still awaiting the review that was done by the senate to take a look at what the staffers actions were. Separation of powers between the executive and legislative branch, senator, goes both ways.”

News of the January 2014 espionage broke two months after it happened, when Sen. Dianne Feinstein (D-Calif.), the ranking member of the intelligence committee and the leader of the probe into Bush-era torture, exposed it on the floor of the Senate. In that speech, she “accused the CIA of ­secretly removing documents, searching computers used by the committee and attempting to intimidate congressional investigators by requesting an FBI inquiry of their conduct,” The Washington Postsaid. The paper noted that Brennan denied the claims “within hours.”

News of the inspector general report’s findings broke in the summer of 2014, when Brennan acknowledged the investigation found improper access of SSCI information by the CIA in January. Agents were attempting to determine if an agency report on Bush-era torture programs assembled by former CIA Director Leon Panetta had been accessed by the SSCI.

But Brennan’s concession angered SSCI staffers, who wanted an admission on the record “that it was wrong,” according to Vice News’ Jason Leopold.

In August, Leopold discovered via FOIA request that Brennan had drafted a statement that contained some admission of wrongdoing, but that he eventually decided against even signing it. Wyden referenced the report when introducing his request.

“Instead, four days later, [Brennan] sent…a different letter–one without an apology or admission that the search of their computer network was improper,” Leopold wrote. “He did say, however, that he was going to ‘stand up’ an ‘independent’ accountability review board…to look into the OIG findings and determine whether the CIA employees who conducted the search should be punished.”

Toward the end of the hearing, Sen. Tom Cotton (R-Ark.) sympathized with Brennan, referring to the alleged unauthorized access by senate staffers. “Handling classified information is a very serious matter, right?” he asked. Brennan responded, calmly: “yes.”

Watch the Senate Intelligence Committee hearing here. Wyden’s questioning starts at around 1:12:30.