A.C.L.U. lawyers said they would urge public disclosure of the contents of the documents. “We intend to press for release of both of these documents,” Jameel Jaffer, a lawyer for the group, said in a statement. “If President Bush and the Justice Department authorized the C.I.A. to torture prisoners, the public has a right to know.”

A spokesman for the C.I.A. declined to discuss the matter.

The documents had been sought by the A.C.L.U. in a suit filed in a New York federal court under the Freedom of Information Act. The suit has previously led to the disclosure of thousands of documents from the Pentagon, the F.B.I., the Justice Department and other agencies.

In the past, C.I.A. lawyers have sought to avoid any discussion of whether the agency had documents related to its interrogation and detention practices, the A.C.L.U. said. The group added that the agency had said national security would be jeopardized if it were compelled to disclose in any way its involvement in interrogations.

In the C.I.A. letter, Mr. McPherson confirmed the existence of the documents but declined to release them, saying that essentially all of their contents were exempt from disclosure under the Freedom of Information Act because release would damage national security and violate attorney-client privilege.

“The documents are withheld in their entirety because there is no meaningful nonexempt information that can be reasonably segregated from the exempt material,” he wrote.