The Pentagon documents released yesterday reveal a gripping internal debate over interrogation tactics for prisoners at Guantanamo Bay, with Pentagon lawyers warning that the military's reputation could suffer as a result of tools approved by Defense Secretary Donald H. Rumsfeld.

In December 2002, as Pentagon officials were trying to get detainees to offer more useful information about al Qaeda, Rumsfeld approved a variety of techniques, such as stripping prisoners to humiliate them, using dogs to scare them and employing stress positions to wear them down, the documents show. The tactics also included using light and sound assaults, shaving facial and head hair and taking away religious items.

Pentagon officials say most of the techniques were never used, and a Pentagon working group recommended that Rumsfeld roll back these methods. In a memo to the defense secretary in March 2003, the group wrote: "When assessing exceptional interrogation techniques, consideration should be given to the possible adverse affects on U.S. Armed Forces culture and self-image, which at times in the past may have suffered due to perceived law of war violations."

As has been previously reported, Rumsfeld did subsequently rescind approval for the most aggressive tactics, including the use of dogs and stripping prisoners. But the documents released yesterday reveal many new details of the behind-the-scenes deliberations over what would be permitted at the Guantanamo Bay prison in Cuba, the holding facility for about 600 detainees picked up in the U.S. campaign against terrorists over the past three years.

For instance, during an initial Pentagon review of the tactics being used at Guantanamo, completed Nov. 27, 2002, Rumsfeld added a handwritten note to the bottom of a document in which he approved new interrogation techniques that included forcing prisoners to stand for four hours at a time. "However, I stand for 8-10 hours a day. Why is standing limited to 4 hours?"

The documents also show commanders and lawyers debating the legality of certain techniques and being torn between what they considered vague guidance offered by past legal cases and the desire to provide useful intelligence to thwart future terrorist attacks.

On Oct. 11, 2002, for example, the commanding general at the Guantanamo Bay detention center, Maj. Gen. Michael Dunlavey, asked his commander to approve the use of death threats against detainees and their families, wrapping a detainee in wet towels to "induce the misperception of suffocation," stress positions, exposing them to cold weather and water, and using dogs.

These techniques had been reviewed and deemed legal under the Geneva Conventions by Dunlavey's legal adviser, Lt. Col. Diane Beaver, who wrote that they would be permissible "so long as there is an important governmental objective" and the tactics are not used "for the purpose of causing harm or with the intent to cause prolonged" mental or physical suffering.

But Dunlavey's commander, Gen. James T. Hill, chief of U.S. Southern Command, expressed unease with this interpretation and asked the chairman of the Joint Chiefs of Staff, Gen. Richard B. Myers, for guidance. "I am uncertain whether all the techniques . . . are legal under US law, given the absence of judicial interpretation of the US torture statute," Hill wrote on Oct. 25, 2002. "I am particularly troubled by the use of implied or express threats of death of the detainee and his family."

A month later, the Pentagon's general counsel, William J. Haynes II, approved the use of dogs and stripping, but threw out the other more controversial methods. He also approved "grabbing, poking in the chest with the finger, and light pushing" among a list of two dozen other tactics.

In a memo dated Nov. 27, 2002, Haynes said that while the tougher techniques "may be legally available . . . we believe our armed forces are trained to a standard of interrogation that reflects a tradition of restraint."