Medical personnel apparently experimented on terror detainees during CIA-led torture after the September 11 attacks, aiming to improve interrogation techniques, a human rights group said Monday.

"There is evidence that they were calibrating the harm inflicted by these techniques allegedly and also looking to extend their knowledge about the effects," said Nathaniel Raymond, from Physicians for Human Rights.

The group said it had used public records showing health professionals worked under the supervision of the Central Intelligence Agency during interrogations of "war on terror" detainees after the 2001 attacks.

The doctors and medical staff witnessed waterboarding, forced nudity, sleep deprivation, temperature extremes and prolonged isolation among other techniques.

"What we see is doctors collecting data that is used to draw conclusions related to whether or not the techniques or behaviors that they are observing violate the Department of Justice standard on what constitutes a level of harm, what makes it torture," Raymond told a press conference.

The experimentation and research "appear to have been performed to provide legal cover for torture," the group said, as it called for an inquiry. 

It has been very disappointing over the last few years that the there has been no active investigation of any allegations that has been made," John Bradshaw, the group's chief policy officer, said.

The report said that in the case of waterboarding -- a technique that simulates drowning -- medical teams advised replacing plain water with saline solution.

This was done "ostensibly to reduce the detainees' risk of contracting pneumonia and or hyponatremia, a condition of low sodium levels in the blood caused by free water intoxication, which can lead to brain edema and herniation, coma, and death," the report said.

CIA rejects report
 
But a CIA spokesman rejected the report as "just wrong." 

The CIA did not, as part of its past detention program, conduct human subject research on any detainee or group of detainees," said spokesman George Little.

He added the detention program had been subjected to multiple internal reviews.

Although the use of cruel and inhuman treatment has been documented before, the report said the new evidence shows health professionals actively participated in research and experimentation on detainees.

"Such acts may be seen as the conduct of research and experimentation by health professionals on prisoners, which could violate accepted standards of medical ethics, as well as domestic and international law," the report said.

"These practices could, in some cases, constitute war crimes and crimes against humanity."

Medical personnel "were ostensibly responsible for ensuring that the legal threshold for 'severe physical and mental pain' was not crossed by interrogators," it added.

"Not only are these alleged acts gross violations of human rights law, they are a grave affront to America's core values," the report said.

"The CIA appears to have broken all accepted legal and ethical standards put in place since the Second World War to protect prisoners from being the subjects of experimentation," said Frank Donaghue, chief executive of the organization.

The report called on President Barack Obama to order "an immediate criminal investigation of alleged illegal human experimentation."

It also called for a probe of violations by the CIA of protections against human research experiments and for Congress to amend the War Crimes Act "to eliminate changes made to the act in 2006 which weaken the prohibition on biological experimentation on detainees."

The physician's group said the latest revelations suggested that Geneva Conventions, the Nuremberg Code and US ethical codes had been broken.

"In their attempt to justify the war crime of torture, the CIA appears to have committed another alleged war crime -- illegal experimentation on prisoners," said Raymond.

"We believe it to be the tip of the iceberg and there is a need for a comprehensive investigation, the need for accountability, the need to prevent that this ever happens again," said Allen Keller, from the Program for the Survivors of Torture.
 
Source: AFP