The documents show both a cover-up attempt and confirmation by a medical doctor:

The detainee withdrew his charges on November 23 2003. He says he was told: "You will stay in the prison for a long time, and you will never get out until you are 50 years old."

A medical examination by a US military doctor confirmed the detainee's account, yet the investigation was closed last October. "It is further proof that the army is not seriously investigating credible allegations of abuse," said Jameel Jaffar, a lawyer for the ACLU.

Two more former prisoners have come forward:

In a separate case, which the Guardian reveals today, two former prisoners of the US in Afghanistan have come forward with claims against their American captors.

In sworn affidavits to a British-American human rights lawyer, a Palestinian says he was sodomised by American soldiers in Afghanistan. Another former prisoner of US forces, a Jordanian, describes a form of torture which involved being hung in a cage from a rope for days.

The prisoners have since been freed. Neither was ever charged with a crime.

Hussain Adbulkadr Youssouf Mustafa, a Palestinian living in Jordan, told the lawyer, Clive Stafford-Smith, that he was sodomised by US soldiers during his detention at Bagram air force base in 2002. He claims to have been blindfolded, tightly handcuffed, gagged and had his ears plugged, forced to bend down over a table by two soldiers, with a third soldier pressing his face down on the table, and to have had his trousers pulled down.

"They forcibly rammed a stick up my rectum," he reports. "It was excruciatingly painful ... Only when the pain became overwhelming did I think I would ever scream. But I could not stop screaming when this happened."

Another prisoner alleges being hung from a hook.

In a second affidavit, the Jordanian citizen, Wesam Abdulrahman Ahmed Al Deemawi, detained from March 15 2002 to March 31 2004, says that during a 40-day period of detention at Bagram he was threatened with dogs, stripped and photographed "in shameful and obscene positions" and placed in a cage with a hook and a hanging rope. He says he was hung from this hook, blindfolded, for two days although he was occasionally given hour-long "breaks".

The Guardian contacted the U.S. for a response.

By the time of going to press last night no response had been received other than an email from a Major Steven Wollman in Kabul, saying he was researching the question.

For more information on the detainees, visit CagedPrisoners , which has photographs and information of 500 detainees, news articles, interviews, current status and in some instances, letters written to family members while in captivity.

The New York Times Friday also reports on the newly released documents.