The CIA acknowledged making videotapes to document interrogations of terrorism suspects that used techniques critics have denounced as torture, and said on Thursday it had destroyed the recordings.

Central Intelligence Agency Director Michael Hayden told employees in a letter that the videotapes were made in 2002 as part of a secret detention and interrogation program that began with the arrest of suspected al Qaeda lieutenant Abu Zubaydah.

The taping was discontinued later that year and the tapes were destroyed in 2005, Hayden said.

The tapes posed a serious security risk. Were they ever to leak, they would permit identification of your CIA colleagues who had served in the program, exposing them and their families to retaliation from al Qaeda and its sympathizers, Hayden said in the letter, a copy of which was obtained by Reuters.

He said he was discussing the program because of pending news reports on it. The New York Times published a story on the tapes on its Web site on Thursday.

The disclosure follows a separate instance last month involving a belated CIA acknowledgment that it possessed interrogation tapes sought in the trial of accused September 11 conspirator Zacarias Moussaoui.

Democrats in both the Senate and House of Representatives called for congressional investigations.

Sen. John Rockefeller of West Virginia, Democratic chairman of the Senate Intelligence Committee, said Congress did not learn about the tapes' destruction until November 2006 -- two months after the full panel was briefed on the interrogation program.

While we were provided with very limited information about the existence of the tapes, we were not consulted on their usage nor the decision to destroy the tapes, Rockefeller said.

DESTRUCTION OF EVIDENCE

Senate Judiciary Committee Chairman Patrick Leahy, a Vermont Democrat, said the tapes' destruction was another troubling aspect of the interrogation program. The damage is compounded when such actions are hidden away from accountability, he said in a statement.

The news also drew fire from the American Civil Liberties Union, which has mounted a legal effort to acquire Justice Department documents it believes authorized harsh interrogations.

The destruction of these tapes suggests an utter disregard for the rule of law. It was plainly a deliberate attempt to destroy evidence that could have been used to hold CIA agents accountable for the torture of prisoners, ACLU National Security Project Director Jameel Jaffer said in a statement.

The detention and interrogation program was confirmed by President George W. Bush in 2006. Under it, terrorism suspects have been subjected to harsh interrogation methods, including a form of simulated drowning known as waterboarding.

Many countries, U.S. lawmakers and human rights groups have denounced waterboarding as torture. It is believed three high-value CIA detainees were subjected to waterboarding and that technique has not been used in the program since 2003.

NO DETAILS

CIA spokesman George Little declined to characterize details of the videotaped interrogations.

Hayden said in the letter that new techniques were needed to obtain information from Zubaydah and others.

He said the techniques were lawful, safe and effective, and approved by the Justice Department and executive branch. But the CIA wanted to make sure it was within the law, So, on its own, the CIA began to videotape interrogations, he said.

He said the CIA stopped the taping because officials concluded it was not needed as a backup to the agency's other means of documenting interrogations. It destroyed the tapes after making sure they had no more intelligence value and were not relevant to any inquiries.

Federal prosecutors revealed last month the CIA erroneously told a court in the Moussaoui case it did not have any interrogation recordings of certain enemy combatants, when it in fact had two videotapes and an audiotape.

Moussaoui pleaded guilty and was sentenced to life in prison.

(Editing by Peter Cooney)