* "Highest officials" bear some blame for torture-report
* Calls on Obama to shut Guantanamo camp by end of 2014
* Report comes in midst of hunger strike at Guantanamo (Adds details paragraphs 10, 16, 19, 26)
An independent task force issued a damning review of Bush-era interrogation practices on Tuesday, saying the highest U.S. officials bore ultimate responsibility for the "indisputable" use of torture, and it urged President Barack Obama to close the Guantanamo detention camp by the end of 2014.
In one of the most comprehensive studies of U.S. treatment of terrorism suspects, the panel concluded that never before had there been "the kind of considered and detailed discussions that occurred after 9/11 directly involving a president and his top advisers on the wisdom, propriety and legality of inflicting pain and torment on some detainees in our custody."
"It is indisputable that the United States engaged in the practice of torture," the 11-member task force, assembled by the nonpartisan Constitution Project think tank, said in their 577-page report.
The scathing critique of methods used under the Republican administration of former President George W. Bush also sharpened the focus on the plight of inmates at Guantanamo, which Bush opened and his Democratic successor has failed to close.
Obama banned abusive interrogation techniques such as waterboarding when he took office in early 2009, but the military prison at the U.S. Naval Base in Cuba has remained an object of condemnation by human rights advocates.
A clash between guards and prisoners at the Guantanamo Bay camp last weekend and the release of harrowing accounts by inmates about force-feeding of hunger strikers threw a harsh spotlight on the predicament of the inmates, many held without charge or trial for more than a decade.
The task force deemed indefinite detention of prisoners at Guantanamo "abhorrent and intolerable" and called for it to be closed by the end of 2014 when NATO's combat mission in Afghanistan is due to end and most U.S. troops will leave.
By then, the 166 Guantanamo prisoners should be tried in civilian or military courts, repatriated or transferred to countries that would not torture them, or moved to U.S. jails, the task force's majority recommended.
But the 2014 goal will be hard to achieve because of legal, legislative and political obstacles Obama faces. While the White House says he remains committed to shutting Guantanamo, he has offered no new path to doing so in his second term.
Panel members said they have offered to meet Obama aides to discuss their findings but had received no response so far.
The release of the encyclopedic report comes in the midst of the latest round of allegations of abuse at Guantanamo, which has become an enduring symbol of widely criticized Bush-era counterterrorism practices. Military officials say 43 prisoners are currently on a hunger strike there.
Members of the task force described themselves as the closest thing to a "truth commission" since Obama decided early in his presidency against convening a national investigation of post-9/11 practices.
The panel, which included leading politicians from both parties, two U.S. retired generals and legal, medical and ethics scholars, spent two years examining the U.S. treatment of suspected militants detained after the Sept. 11, 2001, attacks.
Panel members interviewed former Clinton, Bush and Obama administration officials, military officers and former prisoners, and the investigation looked at U.S. practices at Guantanamo, in Afghanistan and Iraq and at the CIA's former secret prisons overseas.
The task force was chaired by Asa Hutchinson, a Republican former congressman and undersecretary of the Department of Homeland Security during the George W. Bush administration, and James Jones, a Democratic former congressman who served as U.S. ambassador to Mexico.
While acknowledging that Bush-era policymakers were driven by fears of further attacks, the panel insisted this was no excuse for resorting to torture, which it said "occurred in many instances and across a wide range of theaters."
And the panel concluded there was no "persuasive evidence" that such techniques yielded "significant information of value."
"The nation's highest officials bear some responsibility for allowing and contributing to the spread of torture," the report said, though it did not name names.
While reserving most of its criticism for the former Bush administration, the report also accused Obama of not doing enough to ease official secrecy surrounding detentions.
The task force, while concluding that U.S. and international laws were violated, did not recommend criminal action against anyone involved but it did press for tighter rules to prevent a recurrence of torture.
"We as a nation have to get this right," Hutchinson told a news conference at the National Press Club in Washington.
The panel urged the Obama administration to release as much classified information as possible to help understand what went wrong. "Publicly acknowledging this grave error, however belatedly, may ... help undo some of the damage to our reputation at home and abroad," the report said.
The sweeping report cataloged interrogation techniques such as waterboarding, sleep deprivation and chaining prisoners in painful positions.
The task force concluded that force-feeding hunger striking detainees is "a form of abuse and must end" and called on the United States to abide by international medical standards.
The head of the International Committee of the Red Cross last week expressed opposition to the force-feeding of prisoners and said he urged Obama to do more to resolve the "untenable" legal plight of inmates held there.
In a sign of divisions within the panel itself, Hutchinson was one of two members who dissented on the recommendation to close Guantanamo by the end of next year.
The hunger strike began in February to protest the seizure of personal items from detainees' cells. About a dozen are being force-fed liquid meals through tubes.
Guards swept through communal cell blocks at the camp on Saturday and moved the prisoners into one-man cells.
"The action was taken to ensure the health and safety of the detainees not to 'break' the hunger strike," said Navy Captain Robert Durand, a spokesman for the Guantanamo detention center.