WASHINGTON - A bipartisan Senate report released yesterday says that former Defense Secretary Donald H. Rumsfeld and other top Bush administration officials are directly responsible for abuses of detainees at Guantanamo Bay, Cuba. It also charges that decisions by those officials led to serious offenses against prisoners in Iraq and elsewhere.

The Senate Armed Services Committee report accuses Rumsfeld and his deputies of being the principal architects of the plan to use harsh interrogation techniques on captured fighters and terrorism suspects. It rejected the Bush administration's contention that the policies originated lower down the command chain.

"The abuse of detainees in U.S. custody cannot simply be attributed to the actions of 'a few bad apples' acting on their own," the panel concludes. "The fact is that senior officials in the United States government solicited information on how to use aggressive techniques, redefined the law to create the appearance of their legality, and authorized their use against detainees."

The report, released by Sens. Carl Levin (D., Mich.) and John McCain (R., Ariz) and based on a nearly two-year investigation, said both the policies and resulting controversies tarnished the reputation of the United States and undermined national security. "Those efforts damaged our ability to collect accurate intelligence that could save lives, strengthened the hand of our enemies, and compromised our moral authority," it said.

The panel's investigation, some of which has been reported previously, focused on the Defense Department's use of controversial interrogation practices, including forced nudity, painful stress positions, sleep deprivation, extreme temperatures and use of dogs.

"The Committee's report details the inexcusable link between abusive interrogation techniques used by our enemies who ignored the Geneva Conventions and interrogation policy for detainees in U.S. custody," McCain, himself a former prisoner of war in Vietnam, said in a statement. "These policies are wrong and must never be repeated."

White House officials have maintained the measures were approved in response to demands from field officers who complained that traditional interrogation methods were not working on some of the more hardened captives.

The decision to use coercive techniques, the report said, arose from a memo signed by Bush on Feb. 7, 2002, declaring that the Geneva Convention's standards for humane treatment did not apply to captured al-Qaeda and Taliban fighters.

In July 2002, Rumseld's staff compiled information about techniques used in military survival schools to simulate conditions that U.S. airmen might face if captured by an enemy that did not follow the Geneva conditions. Those techniques included waterboarding, or simulated drowning, and that program became the template for interrogation methods that were ultimately approved by Rumsfeld himself, the report says.

In the field, U.S. military interrogators used the techniques with little oversight and frequently abusive results, the panel found.

Defenders of the techniques have argued that such measures were justified because of al-Qaeda's disregard for human life. But panel members cited the views of Gen. David H. Petraeus, now head of U.S. Central Command, who in a May 2007 letter to his troops said humane treatment of prisoners allowed Americans to occupy the moral high ground.

"Our values and the laws governing warfare teach us to respect human dignity, maintain our integrity, and do what is right," Petraeus wrote. "Adherence to our values distinguishes us from our enemy."