The CIA fired a long-serving intelligence officer for sharing classified information with The Washington Post and other news organizations, officials said yesterday, as the agency continued an aggressive internal search for anyone who may have discussed intelligence with the news media.

CIA officials said the career intelligence officer failed more than one polygraph test and acknowledged unauthorized contacts with reporters. The "officer knowingly and willfully shared classified intelligence, including operational information" with journalists, the agency said in a statement yesterday.

The CIA did not reveal the identity of the employee, who was dismissed Thursday, but NBC News reported last night she is Mary McCarthy. An intelligence source confirmed that the report was accurate.

McCarthy began her career in government as an analyst at the CIA in 1984, public documents show. She served as special assistant to the president and senior director for intelligence programs at the White House during the Clinton administration and the first few months of the Bush administration. She later returned to the CIA. Attempts to reach her last night were unsuccessful.

The CIA's statement did not name the reporters it believes were involved, but several intelligence officials said The Post's Dana Priest was among them. This week, Priest won the Pulitzer Prize for beat reporting for articles about the agency, including one that revealed the existence of secret, CIA-run prisons in Eastern Europe and elsewhere.

CIA Director Porter J. Goss told the Senate intelligence committee in February that the agency was determined to get to the bottom of recent leaks, and wanted journalists brought before a federal grand jury to reveal their sources. Regarding disclosures about CIA detention and interrogation of terrorist suspects at secret sites abroad, Goss, the former chairman of the House intelligence committee, said that "the damage has been very severe to our capabilities to carry out our mission."

The CIA has filed several reports to the Justice Department since last fall regarding the publication of classified information and has launched its own internal inquiries which include administering polygraphs to dozens of employees. The intelligence agency is sharing its findings with the Justice Department but is continuing to pursue some avenues of investigation on its own.

"It's up to the Justice Department to decide whether they want to pursue investigations separately," an intelligence source said.

The Justice Department is conducting several leak inquiries, including one into reports last December in the New York Times about a secret domestic surveillance program by the National Security Agency. Officials said it is possible the department could file criminal charges in connection with that investigation and others, but it is unclear whether the department is also investigating the disclosures about CIA-run prisons.

Justice Department spokesman Brian Roehrkasse declined to comment yesterday. "We do not confirm investigations on intelligence-related matters," he said, because of the information's sensitivity.

Intelligence officials, speaking on the condition of anonymity, said the dismissed officer identified by others as McCarthy has not been charged with any crime and is not believed to be the subject of a Justice Department investigation.

The officer's employment was terminated for violating a secrecy agreement all employees are required to sign when they join the agency. The agreement prohibits them from sharing classified information with unauthorized individuals.

The CIA said the firing was the result of an internal investigation initiated in late January of all "officers who were involved in or exposed to certain intelligence programs."

"Through the course of these investigations a CIA official acknowledged having unauthorized discussion with the media" and was terminated, the CIA statement said.

Priest, who also won the George Polk Award and a prize from the Overseas Press Club this week for her articles, declined to comment yesterday.

Post Executive Editor Leonard Downie Jr. said people who provide citizens the information they need to hold their government accountable should not "come to harm for that."

"The reporting that Dana did was very important accountability reporting about how the CIA and the rest of the U.S. government have been conducting the war on terror," Downie said. "Whether or not the actions of the CIA or other agencies have interfered with anyone's civil liberties is important information for Americans to know and is an important part of our jobs."

In an effort to stem leaks, the Bush administration launched several initiatives earlier this year targeting journalists and national security employees. They include FBI probes, extensive polygraphing inside the CIA and a warning from the Justice Department that reporters could be prosecuted under espionage laws.

The effort has been widely seen among members of the media, and some legal experts, as the most extensive and overt campaign against leaks in a generation, and has worsened the already-tense relationship between mainstream news organizations and the White House.

Dozens of employees at the CIA, the National Security Agency and other intelligence agencies have been interviewed by agents from the FBI's Washington field office. Others have been prohibited, in writing, from discussing even unclassified issues related to the domestic surveillance program. Some GOP lawmakers are also considering tougher penalties for leaking.

Pat Roberts (R-Kan.), who chairs the Senate intelligence panel, welcomed the CIA's actions. In a statement, he said leaks had "hindered our efforts in the war against al Qaeda," although he did not say how.

"I am pleased that the Central Intelligence Agency has identified the source of certain unauthorized disclosures, and I hope that the agency, and the [intelligence] community as a whole, will continue to vigorously investigate other outstanding leak cases," Roberts said.

Staff writer Spencer S. Hsu and research editor Lucy Shackelford contributed to this report.