An alleged enemy combatant who has been held in U.S. military custody for more than two years filed a lawsuit yesterday alleging that he has suffered "inhumane, degrading and physically and psychologically abusive treatment" in a military brig in South Carolina.

The 30-page complaint by Ali Saleh Kahlah Marri provides a rare glimpse into one of the most secretive facets of the U.S. government's anti-terrorism strategy, which includes a variety of detention tactics aimed at holding suspected terrorists outside the traditional U.S. criminal justice system.

Marri's allegations also come amid continuing allegations of mistreatment and abuse of detainees at Guantanamo Bay, Cuba, and other U.S. military and intelligence facilities.

Administration officials have repeatedly said that military detainees are treated humanely. Navy Lt. Cmdr. Flex Plexico, a Defense Department spokesman, declined to comment on Marri's lawsuit because it is "a legal matter." But Plexico said that "allegations of this nature have been proven false in the past, and we know that enemy combatants have been trained to make sensational claims about their detention if captured."

Both Marri and Jose Padilla, a former gang member from Chicago, are alleged al Qaeda operatives who have been held without charges after being declared enemy combatants by President Bush. Yaser Hamdi, another alleged enemy combatant, was released and allowed to return home to Saudi Arabia last October after he renounced his claim to U.S. citizenship.

Unlike Padilla, a U.S. citizen, and Hamdi, who was born in Louisiana, Marri is a citizen of Qatar, a fact that has sharply limited his ability to challenge his detention in U.S. courts. A federal judge ruled last month that the Bush administration could continue holding him.

Marri, 39, has been held in solitary confinement at the Naval Consolidated Brig in Charleston, S.C., since June 2003 and has had no direct contact with his family or anyone outside the prison other than his attorneys and representatives of the International Red Cross, according to the suit. Held in a 6-by-9-foot cell, Marri has routinely been denied water, soap, a toothbrush and other necessities and has not been treated for a possible nerve condition, the suit alleges.

The complaint says U.S. interrogators threatened to turn him over to Egypt or Saudi Arabia, where "he would be tortured and sodomized and where his wife would be raped in front of him." His captors also falsely claimed that his brothers and father had been jailed but would be released if he cooperated, the suit says.

"He's been completely cut off from the world and from any kind of mental stimulation," said Jonathan Hafetz, one of Marri's attorneys. "Even if they can detain him, they cannot hold him under the conditions and mistreatment he's been subjected to."

The suit portrays Marri as a devout Muslim who has been thwarted in his efforts to worship regularly and has been punished for covering his head with his shirt while praying. Guards have mistreated his Koran by placing it on the floor and throwing items on it, the suit says.

The lawsuit also says that Marri has not been allowed to have any newspapers, books or reading material other than the Koran; that he has been denied socks or shoes for months; that his cell is extremely cold; and that he is rarely allowed outside for exercise.

Marri arrived in the United States on Sept. 10, 2001, with his wife and five children and enrolled in graduate school at Bradley University in Peoria, Ill., where he had received a bachelor's degree. He was arrested by the FBI in December 2001 as a material witness in connection with the FBI's Sept. 11 investigation and -- after initially being charged with financial crimes -- was declared an enemy combatant in June 2003.

Bush alleged that Marri was "closely associated with al Qaeda," has engaged in preparations for a terrorist attack and "represents a continuing, present and grave danger" to U.S. national security, according to court documents. Most other details about Marri's alleged activities are classified. One of his brothers, Jarallah, is detained at Guantanamo Bay, according to the Pentagon and his lawyers.

Marri has denied the allegations, his attorneys said.

Ali Saleh Kahlah Marri has been held without being charged.