An Afghan detainee is carried on a stretcher before being interrogated by military officials at the prison in Guantanamo Bay, Cuba, in 2002. A study of former Guantanamo detainees has unearthed evidence that they were tortured and abused. (Lynne Sladky/Associated Press)

Medical examinations of suspected militants formerly held by the U.S. military at the Guantanamo Bay detention centre in Cuba showed evidence of torture and other abuse that resulted in serious injuries and mental disorders, according to a human rights group.

The study, considered the most extensive medical check of former U.S. detainees published so far, also tracked former suspects held at the Abu Ghraib prison in Iraq, with similar findings.

For the study, Physicians for Human Rights had doctors and mental health professionals examine 11 former prisoners of Abu Ghraib and Guantanamo Bay.

The U.S-based human rights organization says it found evidence of U.S. torture and war crimes, and it accuses U.S. military health professionals of allowing the abuse of detainees, denying detainees medical care and providing confidential medical information to interrogators that was then exploited.

Physicians for Human Rights did not identify the 11 former prisoners to protect their privacy. Seven were held in Abu Ghraib between late 2003 and summer of 2004, a period that coincides with the known torture of prisoners at the hands of some of their U.S. jailers. Four of the prisoners were held at Guantanamo beginning in 2002 for one to almost five years. All 11 were released without charges being laid.

Those examined reported being tortured or abused, including sexually, and described being shocked with electrodes, beaten, shackled, stripped of their clothes, deprived of food and sleep, and spit and urinated on.

Prisoner subjected to electrical shocks 3 times a day

The Associated Press has obtained a report outlining the treatment of two Iraqi prisoners. One, identified only as Yasser, reported being subjected to electric shocks three times and being sodomized with a stick. His thumbs bore round scars consistent with shocking. He would not allow a full rectal exam.

Another Iraqi, identified only as Rahman, reported he was humiliated by being forced to wear women's underwear, was stripped naked and paraded in front of female guards, and was shown pictures of other naked detainees. The psychological exam found that Rahman suffered from post-traumatic stress disorder and had sexual problems related to his humiliation.

The Physicians for Human Rights report came as the U.S. Senate's armed services committee revealed documents showing military lawyers warned the Pentagon that methods it was using following the Sept. 11, 2001, airplane hijackings violated military, U.S. and international law. Those objections were overruled by a top Pentagon lawyer.

U.S. President George W. Bush said in 2004, when the prison torture was revealed, that it was the work of "a few American troops who dishonoured our country and disregarded our values." Bush and other U.S. officials have consistently denied that the U.S. tortures its detainees.

The degradation of some prisoners by their U.S. captors is well documented by the government's own reports. Once-secret documents show that the Pentagon and Justice Department allowed, at least for a time, forced nakedness, isolation, sleep deprivation and humiliation at its military prisons in Guantanamo Bay and at Abu Ghraib.

Health of detainees prior to detention not known

Physicians for Human Rights' medical examiners did not have access to the 11 patients' medical histories prior to their imprisonment, so it was not possible to know whether any of the prisoners' ailments, disabilities and scars pre-dated their confinement. The U.S. military says an al-Qaeda training manual instructs members, if captured, to assert they were tortured during interrogation.

However, doctors and mental health professionals stated they could link the prisoners' claims of torture while in U.S. detention to injuries documented by X-rays, medical exams and psychological tests.

"The level of the time, thoroughness and rigour of the exams left me personally without question about the credibility of the individuals," said Dr. Allen Keller, one of the doctors who conducted the exams, in an interview with the Associated Press.

"The findings on the physical and psychological exams were consistent with what they reported."

All 11 former detainees reported being subjected to:

• Stress positions, including being suspended for hours by the arms or tightly shackled for days.
• Prolonged isolation and hooding or blindfolding, a form of sensory deprivation.
• Threats against themselves, their families or friends from interrogators or guards.
• Ten said they were forced to be naked, some for days or weeks.
• Nine said they were subjected to prolonged sleep deprivation.
• At least six said they were threatened with military working dogs, often while naked.
• Four reported being sodomized, subjected to anal probing, or threatened with rape.

The patients underwent intensive, two-day long exams following standards and methods used worldwide to document torture.

"We found clear physical and psychological evidence of torture and abuse, often causing lasting suffering," Keller said.

Keller, who directs the Bellevue/New York University Program for Survivors of Torture, said the treatment the detainees reported were "eerily familiar" to stories from other torture survivors around the world. He said the sexual humiliation of the prisoners was often the most traumatic experience.

Most former detainees are out of reach of Western doctors because they are either in Iraq or have been returned to their home countries from Guantanamo.

More than 770 prisoners have spent time at Guantanamo Bay, some for up to six years without charge, since the U.S. invasion of Afghanistan in 2001. Of the 270 men currently being held, 20 have been charged with criminal offences. One conviction has resulted from the Guantanamo detentions, that of Australian David Hicks in 2007.