Updated

U.S. law enforcement agents at the Guantanamo Bay (search), Cuba, prison for terrorism suspects concluded that the military's aggressive questioning yielded information that was "suspect at best," according to newly released portions of an FBI (search ) document.

That conclusion is contained in an internal FBI e-mail message, dated May 10, 2004, that also said the FBI had made it known to Pentagon officials in 2002 that the FBI "has been successful for many years obtaining confessions via non-confrontational interviewing techniques."

The document was released Monday by Sen. Carl Levin (search), D-Mich. Portions that had previously been blacked out were released to Levin after he and Sen. Joe Lieberman (search), D-Conn., asked the Justice Department to reconsider.

Substantial portions of the document remain blacked out, even in the newly released version.

Among the newly released passages was the statement that law enforcement agencies at Guantanamo Bay "were of the opinion (that) results obtained from these interrogations were suspect at best."

This memo did not describe the interrogation techniques and did not say which results were considered suspect.

It added that the Justice Department had made its concerns known to Pentagon officials, who sometimes were at odds with the FBI over acceptable methods of interrogation at Guantanamo Bay, particularly in late 2002. At that time the military was holding what it considered high-value al-Qaida members at Guantanamo Bay, and military officials sought permission to use interrogation techniques that were harsher than allowed under standard military practice.

Defense Secretary Donald H. Rumsfeld approved use of some harsher techniques in December 2002 but rescinded the authority in January 2003 after some inside the military questioned whether they were appropriate. Rumsfeld then convened a committee that eventually set clearer guidelines.

Another FBI e-mail, also dated May 10, 2004, said that in weekly Justice Department meetings, officials had often discussed the military's interrogation techniques and "how they were not effective or producing intel that was reliable." (The term "intel" is short for intelligence.)

Both of those May 10, 2004 e-mail messages were originally labeled "secret" and were addressed to Thomas Harrington, an FBI counterterrorism expert who led a team of investigators to Guantanamo Bay. The name of the author of the memos was blacked out.

Levin said in a statement Monday that the newly released information highlights the fact that Justice Department attorneys had expressed concerns about the military's interrogation techniques.

"Today we were able to obtain some information that had previously been blacked out in an FBI document critical of DoD (Department of Defense) interrogation practices," Levin said. "As I suspected, the previously withheld information had nothing to do with protecting intelligence sources or methods, and everything to do with protecting DoD from embarrassment."

Levin said he has asked the Justice Department why the names of some FBI personnel mentioned in the memos are still being withheld.

William E. Moschella, the Justice Department official who responded to Levin's request that additional portions of the e-mail memos be released, wrote in a letter to Levin that material that remains blacked out includes "text in which the Department of Defense has interests." As a result, Justice has asked the Pentagon's view on whether that text can be released.