U.S. military doctors violated medical ethics by collaborating in the abuse of prisoners during interrogations after the Sept. 11 attacks on the United States in 2001, an independent study concluded on Monday.

“These practices included designing, participating in, and enabling torture and cruel, inhumane and degrading treatment of detainees,” concluded the study by the Task Force on Preserving Medical Professionalism in National Security Detention Centers.

The panel is made up of 19 military, health, legal and human rights experts who studied public records concerning the role of health professionals in detainee operations in Afghanistan and Iraq, at secret CIA prisons and at the Guantánamo Bay U.S. Navy Base in Cuba during the last dozen years.

They said that in the rush to obtain information that could prevent future attacks, the Defense Department and the CIA improperly demanded that medical personnel violate their ethical obligation to “do no harm.”

A Pentagon spokesman, Lt. Col. Todd Breasseale, said detainees receive humane medical care and that the allegations in the report were not new.

“They have been subject to numerous investigations over the years, and those investigations – which had access to more information than the authors of this report – have never substantiated these claims,” Breasseale said.

The report, titled “Abandoned Ethics,” said mental health professionals advised interrogators on how to exploit detainees’ fears and anxieties and when to increase the harshness of interrogations.

They used medical records and psychological profiles to help interrogators create feelings of dependency and dread, and to strip away detainees’ will to resist, the report said.

It quoted former CIA prisoners as saying medical doctors monitored them during so-called enhanced interrogations - checking oxygen levels while one was waterboarded and measuring the swollen limbs of another who was shackled in a standing position for long periods. Sometimes the doctors intervened, the report said.

“The role of physicians at CIA sites, then, was not to prevent pain, suffering, or harm to the detainee, but only to avoid severe harm,” it said.

The task force called for a full investigation.

“We have a responsibility to make sure this never happens again,” said task force member Gerald Thomson, a doctor and professor of medicine emeritus at Columbia University.

After the hijacked plane attacks that killed nearly 3,000 people on 9/11, the Bush administration authorized interrogation techniques that have been characterized as torture.

The CIA no longer holds prisoners and President Barack Obama has prohibited the use of torture and cruel, inhuman and degrading treatment, the report notes.

But it said ethical violations were still occurring, such as the force-feeding of hunger-striking prisoners at Guantánamo.

The report’s authors included Albert Shimkus, a retired Navy captain who was the commanding officer and chief surgeon in charge of detainee health care at the Guantánamo base in 2002 and 2003. He now teaches at the U.S. Naval War College.