Senator Diane Feinstein (D-CA), the head of the Senate Intelligence Committee, said today that the CIA has illegally monitored and searched computers that belong to her committee.

The computers were on a closed network created to investigate claims of CIA abuse related to detention and interrogation programs that began in 2002. Feinstein explained her concerns in a 38-minute speech this morning on the Senate floor. "I have grave concerns that the CIA's search may well have violated the separation of powers principles embodied in the United States Constitution," she said.

Feinstein said the CIA's actions may have violated the Fourth Amendment, which bars “unreasonable searches and seizures,” as well as other federal laws, along with an executive order that prevents the CIA from engaging in domestic surveillance and searches.

Congressional oversight of intelligence agencies, or lack thereof, has been under increased attention since press reports began to appear about leaked National Security Agency documents last summer. In debates about those leaks, Feinstein has emerged as a staunch defender of intelligence agencies.

"I come to the Senate floor reluctantly," said Feinstein. She was alerted of the searches in mid-January and tried to resolve the issue "in a discreet and respectful way," not commenting in response to media requests. But inaccurate information has been published, said Feinstein. "I rise today to set the record straight and to provide a full accounting of the facts and history," she said.

The full text of Feinstein's remarks this morning have been published in The Guardian.

In response, CIA Director John Brennan denied accusations that the CIA took actions to thwart intelligence investigations, explaining, “Nothing could be further from the truth.” Brennan said he would defer to Department of Justice investigators, who are looking into “the possibility of a criminal violation by CIA personnel.” Brennan has further suggested that media coverage of these types of events is harmful to the intelligence community and often distorts intelligence views and activities.