The officer was a senior analyst nearing retirement, Mary McCarthy, The Associated Press learned. Reached Friday evening at home, her husband would not confirm her firing.
In McCarthy's final position at the CIA, she was assigned to its Office of Inspector General, looking into allegations the CIA was involved in torture at Iraqi prisons, according to a former colleague who spoke on condition of anonymity because the case is under investigation.
Without identifying McCarthy by name, CIA Director Porter Goss announced the firing in a brief message to agency employees circulated Thursday. Such dismissals are highly unusual.
U.S. officials tell CBS News that these are the actions of a very aggressive and reinvigorated Inspector General's Office at the CIA and that they are raising "stress and apprehension" among intelligence operatives.
Agency spokesman Paul Gimigliano confirmed an officer had been fired for having unauthorized contacts with the media and disclosing classified information to reporters, including details about intelligence operations.
"The officer has acknowledged unauthorized discussions with the media and the unauthorized sharing of classified information," Gimigliano said. "That is a violation of the secrecy agreement that everyone signs as a condition of employment with the CIA."
Citing the Privacy Act, the CIA would not disclose any details about the officer's identity, assignments or what she might have told the news media. A law enforcement official confirmed there was a criminal leaks investigation under way, but it did not involve the fired CIA officer.
The official said the CIA officer had provided information that contributed to a Washington Post story last year disclosing secret U.S. prisons in Eastern Europe. The law enforcement official spoke only on condition of anonymity, citing the sensitivity of the matter.
The Post's Dana Priest won a Pulitzer Prize this week for her reporting on a covert prison system set up by the CIA after Sept. 11, 2001, that at various times included sites in eight countries. The story caused an international uproar, and government officials have said it did significant damage to relationships between the U.S. and allied intelligence agencies.
Post Executive Editor Leonard Downie Jr. said on the newspaper's Web site: "We don't know the details of why (the CIA employee) was fired, so I can't comment on that. But as a general principle, obviously I am opposed to criminalizing the dissemination of government information to the press."
It was unclear if Priest or any other reporters who spoke to McCarthy would be brought into an investigation. Post spokesman Eric Grant said no reporter at the paper had been subpoenaed or had spoken to investigators about the matter.
CIA Director Porter Goss was livid over the leaks and vowed in an appearance before Congress in February to crack down, reports CBS News correspondent Jim Stewart.
"The damage has been very severe to our capability to carry out our mission. I use the words very severe intentionally," Goss told Congress, adding that a federal grand jury should be impaneled to determine "who is leaking this information."
But some in the intelligence community are supporting McCarthy.
Former CIA analyst Ray McGovern told CBS correspondent Joie Chen that McCarthy is really a whistleblower with no other way to stop what she saw was an agency run amok.
"She saw a war crimes act in progress, she saw no oversight by congress," McGovern said, "so she said 'well alright somebody's got to do it, I'll take the risk.'"
On Friday, another government official, also speaking on condition of anonymity because of the sensitivity of the information, said the fired officer had failed a lie-detector test.
It was not clear if the person was taking a routine polygraph examination, as is required periodically of employees with access to classified information, or if the test was among those ordered by Goss to find leakers inside the agency.
Justice Department officials declined to comment publicly on the firing and whether the matter had been referred to federal prosecutors for possible criminal charges.
Almost immediately, the firing turned political. Senate Intelligence Committee chairman Pat Roberts, R-Kan., praised the agency for identifying a source of the leaks and encouraged vigorous investigation of other open cases. "Those guilty of improperly disclosing classified information should be prosecuted to the fullest extent of the law," Roberts said.
Sen. Robert Menendez, D-N.J., called on President Bush to hold accountable those in his administration who leaked information about the Iraq intelligence in the run-up to the war and outed undercover CIA operative Valerie Plame. "Apparently, President Bush doesn't believe what's good for the CIA is good for the White House," Menendez said.
One law enforcement official said there were dozens of leak investigations under way. Another said there had been no referral from the CIA involving the fired employee, normally a precursor to a criminal investigation.
Both spoke on condition of anonymity because the matter is under investigation.