The motion released Friday detailed for the first time the alleged mistreatment of Salim Ahmed Hamdan, a Yemeni. Hamdan's Navy lawyer claims, among other things, that U.S. forces repeatedly rammed his head into a post in Afghanistan and held him in solitary confinement for long periods at Guantánamo.
He also said Egyptian interrogators painfully twisted Hamdan's bound arms to extract statements in the presence of a U.S. official in Afghanistan, where he was also forced to sit motionless on benches with other prisoners in subfreezing temperatures for days.
Hamdan's statements were the result of ''physical and mental coercion,'' and the judge should not permit them as evidence at a his trial this summer, Navy Lt. Cmdr. Brian Mizer said.
''The government's effort to introduce these statements into a criminal trial heralds a very dark chapter in American history,'' Mizer said.
A military judge is expected to hold a hearing on the motion at Guantánamo later this month and the U.S. government has not yet filed its response.
But a Pentagon spokesman said the U.S. investigates all credible allegations of abuse and noted that al Qaeda trains operatives to make false allegations of torture and mistreatment if taken prisoner.
''Our policy is, and always has been, to treat detainees humanely,'' Navy Cmdr. Jeffrey Gordon said.
Army Maj. Robert Gifford, a spokesman for the U.S. military commissions -- the first American war crimes tribunals since the World War II era -- said any statements obtained through torture cannot be used at the Guantánamo trials.
It would be up to the military judge to decide if the prisoner's treatment constituted torture and could be considered at trial.
Afghan forces captured Hamdan in November 2001 and turned him over to the U.S. He has been at Guantánamo, where about 280 men are held on suspicion of terrorism or links to al Qaeda or the Taliban, since May 2002.
Hamdan is charged with conspiracy and supporting terrorism and faces a possible life sentence if convicted by the military tribunal.
In December, FBI and Defense Department agents testified that Hamdan admitted to interrogators that he was a personal driver for bin Laden, and chauffeured the terrorist leader between various Afghanistan safe houses to avoid U.S. retaliation after the Sept. 11 attacks.
Defense lawyers have asserted the prisoner was just a low-level employee who had no significant role in any attacks against the U.S. Now, they are adding that his statements to interrogators should not be considered valid because of the abusive treatment.
''Mr. Hamdan's statements in Afghanistan were made when he was under fear of beatings, cruel treatment, and even death,'' his attorney wrote. ``Mr. Hamdan's statements at Guantánamo were made under a regime of interrogations and conditions of confinement carefully calibrated alternatively to induce fear and hope and to disorient and confuse, all to extract cooperation and statements.''
At Guantánamo, the treatment included solitary confinement for two to five days before an interrogation, which at one point allegedly included a female interrogator suggestively touching him to affront his Islamic beliefs, his attorney said.
They also withheld letters from his family or denied him outdoor recreation time -- aggravating his sciatica -- if he did not cooperate with interrogators. He eventually cooperated, the lawyer said, because he was told that he would not be prosecuted.
