CIA Director John Brennan has apologized to the leadership of the Senate Intelligence Committee after the CIA's Inspector General determined that agency officials inappropriately searched the stand-alone computer network used by committee staffers in preparing their report on the C.I.A.'s detention and interrogation program. Earlier this year, Brennan denied the C.I.A. had illegally monitored the committee's computers calling the suggestions as "just beyond the scope of reason."

To follow up on the Inspector General's determination Brennan has ordered the formation of an accountability board to review the incident and make recommendations that could potentially lead to disciplinary action.

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The development is the latest twist in a long-running dispute between the CIA and the committee about classified information used to compile the 6,000 page report. The classified report found that the CIA overstated the success of the program and may have misled members of Congress. A declassified summary of the report could be released in a few weeks,

In order for committee staffers to have access to classified materials about the program an agreement was reached in 2009 that allowed them access to documents at a CIA facility in northern Virginia. A standalone computer network, called RDINet, was developed so the staffers could access classified computer files.

In January, Brennan informed committee chairman Sen. Dianne Feinstein and vice-chairman Sen. Saxby Chambliss that the CIA had recently performed a "search" of that network and determined that committee staffers had been given access to files that should not have been on the network. In turn, Feinstein said she believed that the CIA could only have determined that by violating the agreement that the CIA would not have access to the committee's computer network.

At the time Brennan referred the dispute to the CIA's Inspector General.

In a statement released today CIA spokesman Dean Boyd said the Inspector General's investigation had judged "that some CIA employees acted in a manner inconsistent with the common understanding reached between SSCI and the CIA in 2009 regarding access to the RDINet."

"The Director subsequently informed the SSCI Chairman and Vice Chairman of the findings and apologized to them for such actions by CIA officers as described in the OIG report," said Boyd.

The statement added that Brennan has ordered the establishment of an Accountability Board to be chaired by former senator Evan Bayh who served on the Senate Intelligence Committee. "This Board will review the OIG report, conduct interviews as needed, and provide the Director with recommendations that, depending on its findings, could include potential disciplinary measures and/or steps to address systemic issues," said Boyd.

The dispute became public in March when Feinstein delivered a lengthy and blistering speech on the Senate floor where she expressed "grave concerns" that the CIA had conducted an unauthorized search of the network that violated the 2009 agreement. She also asked the CIA to apologize and recognize that the computer search was inappropriate.

Appearing at a Washington think tank the same day as Feinstein's speech, Brennan denied her accusations labeling them "beyond the scope of reason" and that "nothing could be further from the truth." "I mean we wouldn't do that," Brennan told the Council on Foreign Relations. "I mean that's just beyond the scope of reason in terms of what we would do."

On Thursday, Feinstein called Brennan's apology and his decision to refer the Inspector General report to an accountability board "positive first steps."

Other Democratic members of the committee were more critical. Senator Ron Wyden (D-Oregon) called for Brennan to make a "public apology" and Senator Mark Udall (D-Colorado) expressed a loss of confidence in Brennan.

"I am concerned about the director's apparent inability to find any flaws in the agency he leads," Udall said in a statement. "Earlier this year he referred to the chairman's and my publicly stated concerns about the CIA search as 'spurious allegations that are wholly unsupported by facts' and urged us to 'refrain from outbursts.' Brennan needs to account for these statements." Udall said he wants an independent counsel to look into the matter.

Earlier in July the Justice Department said it had found insufficient evidence to proceed with a criminal probe of the Feinstein and CIA's separate allegations.