Brennan was, until recently, President and CEO of The Analysis Corporation, a growing intelligence contractor, as well as chairman of the Intelligence and National Security Alliance, an influential and secretive industry association representing major intelligence contractors.
The director of central intelligence had always been chairman of American intelligence and chief executive of the C.I.A.; he was responsible.
He is currently chairman of the Intelligence and Security Committee, which oversees the UK's intelligence agencies.
On Sunday, Senator Pat Roberts, a Kansas Republican who is chairman of the intelligence committee, said his panel had been briefed on the intelligence that an attack in Saudi Arabia appeared likely.
Sir Malcolm Rifkind, chairman of the Intelligence and Security Committee which oversees the work of the UK's intelligence services, said he expected to see a written report from GCHQ in "the next day or so" about their response to the report.
Senator Bob Graham, a Florida Democrat and chairman of the intelligence committee, told reporters that it was "premature" to label the lack of warning as an intelligence failure.
He suggested that oversight of the intelligence agencies could be improved and raised concerns that a former foreign secretary, Sir Malcolm Rifkind, was chairman of the intelligence and security committee.
Feinstein said she would likely vote against such legislation sponsored by Senator Bob Corker, chairman of the intelligence committee.
Senators Dianne Feinstein, Democrat of California, and Saxby Chambliss, Republican of Georgia, the chairwoman and vice chairman of the intelligence committee, released a joint statement defending the surveillance.
Former Senator Bob Graham of Florida, chairman of the intelligence committee at the time, has said he did not recall discussions of waterboarding during the briefings.
