Citing internal memos and interviews, the Post said the FBI invoked nonexistent terrorism emergencies or persuaded phone companies to provide information as it illegally gathered more than 2,000 records between 2002 and 2006.

The bureau said in 2007 that it had improperly obtained some phone records, and the Justice Department inspector general is expected to release a report this month detailing the extent of the problem.

FBI general counsel Valerie Caproni told the Post that agents technically violated the Electronic Communications Privacy Act, which was enacted in 1986, by citing nonexistent emergencies to collect records. "We should have stopped those requests from being made that way," she said.

Documents obtained by the Post show that FBI managers as high as the assistant director level approved the emergency requests. Caproni said FBI Director Robert Mueller did not know about the requests until late 2006 or early 2007, after the inspector general's investigation had begun.

Caproni told the Post that the bureau will await the inspector general's report before deciding whether disciplinary action is warranted.