The CIA's current techniques for interrogating terrorism suspects are legal and do not include a widely condemned method known as waterboarding, U.S. Attorney General Michael Mukasey told Congress on Tuesday. Mukasey declined, however, in a letter to Senate Judiciary Committee Chairman Patrick Leahy on the eve of testimony before the panel, to say whether he considered waterboarding, a form of simulated drowning, to be illegal.

A U.S. official confirmed last week that waterboarding was used in the past but had not been used for several years.

"The interrogation techniques currently authorized in the CIA program comply with the law," Mukasey wrote Leahy. "A limited set of methods is currently authorized for use in that program. ... Waterboarding is not, and may not be, used in the current program."

Leahy, a Democrat from Vermont, and other lawmakers repeatedly pressed Mukasey in his confirmation hearings last year and afterward to say whether he considered waterboarding an illegal form of torture, as do many human rights groups and other critics.

If Mukasey agreed, it could open the door to prosecution of officials involved in CIA's interrogation program launched after the Sept. 11 attacks. Mukasey, who had said in a letter to the committee before his confirmation that waterboarding is "repugnant to me," said he would review the interrogation program.

But Mukasey told Leahy on Tuesday that since waterboarding was not now in use, he did not feel it appropriate to give an opinion.