In the latest escalation of the battle between the US Senate and the Central Intelligence Agency, Senate majority leader Harry Reid has requested that the CIA suspend at least some interaction with Senate staff while a new investigation into potential spying on Congress proceeds.

Reid, a Democrat, informed CIA director John Brennan late Wednesday that he is instructing the Senate sergeant-at-arms to perform a “forensic examination” of the computer networks at the center of the CIA’s struggle with its overseers on the Senate intelligence committee.

While the examination is underway, Reid wrote to Brennan, “I ask that you take whatever steps necessary to ensure that CIA personnel refrain from further interaction relating to this issue with Senate staff other than the sergeant-at-arms staff.”

Reid’s new inquest signals a personal involvement in the crisis by one of the most powerful figures on Capitol Hill. It also marks the third investigation into potential misconduct centering around yet another inquiry: the Senate intelligence committee’s extensive, years-long, classified study of brutal, torturous interrogations performed by the CIA in the 2000s.

Last week, the intelligence committee chairwoman, Dianne Feinstein of California, who is normally sympathetic to the national security establishment, publicly accused the CIA of spying on a committee computer network established by the agency in 2009 to facilitate the committee’s access to classified documents. She called the alleged act an attempt to intimidate the panel away from its conclusions about CIA involvement in torture.

Feinstein, in an extraordinary Senate floor speech, said the CIA had transgressed its constitutional boundaries and prompted a crisis, one that the CIA inspector general is examining.

The CIA has not backed down. It holds that Senate staff improperly accessed CIA networks to get hold of a classified document, called the “Internal Panetta Review” by the Senate, and referred a criminal inquiry on the staffers to the Justice Department.

Unsurprisingly, Reid is backing Feinstein, a senior member of his party and his legislative body.

“To my knowledge, the CIA has produced no evidence to support its claims that Senate committee staff who have no technical training somehow hacked into the CIA’s highly secured classified networks, an allegation that on its face seems patently absurd,” Reid wrote to Brennan.

Feinstein admitted on the Senate floor last week that her staff removed a physical copy of the Internal Panetta Review from a secured facility in Virginia set up for committee use last year, a step she defended, saying the committee’s access to the document appeared inadvertent and the CIA had a history of surreptitiously removing material it had provided the committee.

At the heart of the current crisis is a set of secret rules that neither the CIA nor the committee have disclosed.

In 2009, the CIA and the committee established the rules for committee access to a classified computer network that the CIA set up for the panel. The rules supposedly establish the boundaries of each party’s access to each other’s use of the network, parts of which are hived off from the other. Aspects of the accord, some of which is said to be classified, emerged in Feinstein’s floor speech and in a CIA court filing in February.

Both parties say the other transgressed the accord, either in spirit or in letter. The CIA holds that it did not spy on the committee, but rather examined who had access to the Internal Panetta Review as part of basic counterintelligence computer hygiene. The Senate committee holds that the CIA crossed over a digital border established to protect the legislative body’s independent review of the interrogation-related documents.



Reid referred to the arrangement by saying the CIA had conducted a “search” on “computers and computer networks established for exclusive SSCI use”, using the acronym for the Senate intelligence panel.

But neither side has yet released the agreement, permitting each side to characterize the other as violating it without a public point of reference – another indication that the conflict has yet to run its course.

CIA spokesman Dean Boyd said the agency wanted to de-escalate the situation.

“CIA director Brennan is committed to resolving all outstanding issues related to the Senate select committee on intelligence's rendition, detention and interrogation report and to strengthening relations between the agency and Congress,” Boyd said in a statement provided to the Guardian.

“The CIA believes in the necessity of effective, strong and bipartisan congressional oversight. We are a far better organization because of congressional oversight, and we will do whatever we can to be responsive to the elected representatives of the American people.”

Steven Aftergood, an intelligence policy expert at the Federation of American Scientists, said the row risked being “poisonous if it’s not dealt with promptly”.

Limiting the CIA’s interaction with the Senate staff carries the “mildly hostile implication that the CIA personnel might interfere with the Senate investigation,” Aftergood said.

Reid has the power to add force to that implication. The Senate committee passed the intelligence agencies’ annual budget authorization in November. But it has yet to come to the Senate floor, whose schedule Reid largely controls.

Whether or not Reid is correct to imply the CIA would tamper with the Senate torture inquiry, Aftergood said, “it’s a sign of assertiveness from the Senate leader and so it ratchets up the tension a notch or two.”