"There must be a complete and independent investigation of what happened in Guantanamo, Abu Ghraib and other places where terrorist suspects were detained," Allen Keller of Physicians for Human Rights (PHR) told a briefing in the US House of Representatives Thursday.

"We urge that a full investigation in the form of an independent non-partisan commission that has access to all documents and has subpoena power to obtain relevant documents as well as the testimony of officials," PHR president Leonard Rubenstein said.

"There must be accountability... accountability must include prosecuting individuals who have committed war crimes, whatever their place in the chain of command," he added.

The doctors described graphically how detainees held at the US naval base at Guantanamo Bay, Cuba and in Iraq and Afghanistan had been subjected to "torture and abuse while in US custody that was sadly second to none."

The ordeals suffered by the 11 detainees, all of whom have been released without charge, were outlined in a report compiled by PHR and released three weeks ago.

Keller told how one former Guantanamo prisoner who was interviewed for the report was beaten, stripped naked, subjected to intimidation by dogs, hooded, thrown against a wall and sustained electric shocks from a generator.

He also endured sexual humiliation, including an incident where "a naked woman entered the interrogation room and smeared him with what he believed to be menstrual blood."

Another prisoner was "forced to lie face-down in urine and sodomized with a broomstick," Keller said.

"As a physician and scientist who has spent much of his professional career evaluating and caring for victims of torture and abuse, I want to clearly state that torture and inhuman interrogation techniques are cruel, ineffective and can have devastating health consequences," Keller said.

"I am very concerned that when we as a country condone such methods, we are putting our soldiers and other US citizens living around the world at risk," he added.

"We have violated the golden rule that we preached for years: don't torture. So what do we do? We change the name. We called it 'enhanced interrogation techniques'," Keller said.

PHR president Rubenstein echoed the call for a probe.

"Accountability must include prosecuting individuals who have committed war crimes, whatever their place in the chain of command," said Rubenstein.

In the preface to the PHR report entitled "Broken Laws, Broken Lives: Medical evidence of torture by US personnel and its impact," retired US Army general Antonio Teguba said bluntly that there was "no longer any doubt that the current administration has committed war crimes."

"The only question that remains to be answered is whether those who ordered the use of torture will be held to account," said Teguba, who led the official investigation into the Abu Ghraib prisoner abuse scandal in Iraq.

Abu Ghraib prison became infamous after the publication in 2004 of photographs showing Iraqi detainees being humiliated and abused by their US guards. The scandal led to the sentencing of 11 US soldiers to up to 10 years in prison.

Physicians for Human Rights shared the Nobel Peace Prize in 1997 as one of the original steering committee members of the International Campaign to Ban Landmines.

© 2008 Agence France-Presse