"The next time that detainee was interviewed, his level of cooperation was diminished."

Many agents assigned to Iraq and Cuba reported witnessing incidents of abuse by military units or civilian contractors.

In a June "Urgent Report" to the FBI director from the Sacramento field office, for example, a supervising special agent described abuses such as "strangulation, beatings, placement of lit cigarettes into the detainees' ear openings and unauthorized interrogations."

The supervisor added that some officials "were engaged in a cover-up of these abuses."

In other instances, a female prisoner "indicated she was hit with a stick," according to a memo from last May, and in July, Army criminal investigators were reviewing "the alleged rape of a juvenile male detainee at Abu Ghraib prison."

Still other agents gave more detailed accounts of abuse.

In June, for instance, an agent from the Washington field office reported that an Abu Ghraib detainee was "cuffed" and placed into a position the military called "The Scorpion" hold. Then, according to what the prisoner told the FBI, he was doused with cold water, dropped onto barbed wire, dragged by his feet and punched in the stomach.

In Cuba, a detainee in May, 2002, was reportedly spat upon and then beaten when he attempted to roll onto his stomach to protect himself. At one point, soldiers apparently were "beating him and grabbed his head and beat it into the cell floor," knocking him unconscious.

Another agent reported this past August that while in Cuba he often saw detainees chained hand and foot in a fetal position on the floor "with no chair, food or water."

"Most times they had urinated or defecated on themselves, and had been left for 18-24 hours or more," the agent wrote.

Sometimes, he reported, the room was chilled to where a "barefooted detainee was shaking with cold." Other times, the air-conditioning was turned off and the temperature in the unventilated room rose to well over 100 degrees.

"The detainee was almost unconscious on the floor, with a pile of hair next to him," the agent reported. "He had apparently been literally pulling his own hair out throughout the night."

The FBI documents also included a report about a prisoner in Cuba whose legs were injured and who said he lied about being a terrorist for fear that otherwise the U.S. military would amputate him.

"He indicated he was injured severely and in a lot of pain," the FBI wrote. Yet the prisoner constantly was being asked whether he had attended a terrorist camp in Afghanistan.

The agent wrote that the prisoner "stated he wanted to receive decent medical treatment, and felt the only way to get it was to tell the Americans what they wanted to hear."