A suspected terrorist who spent years in a secret CIA prison should not be allowed to speak to a civilian attorney, the Bush administration argues, because he could reveal the agency's closely guarded interrogation techniques.

Human rights groups have questioned the CIA's methods for questioning suspects, especially following the passage of a bill last month that authorized the use of harsh — but undefined — interrogation tactics.

In recently filed court documents, the Justice Department said those methods, along with the locations of the CIA's network of prisons, are among the nation's most sensitive secrets. Prisoners who spent time in those prisons should not be allowed to disclose that information, even to a lawyer, the government said.

"Improper disclosure of other operational details, such as interrogation methods, could also enable terrorist organizations and operatives to adapt their training to counter such methods, thereby obstructing the CIA's ability to obtain vital intelligence that could disrupt future planned terrorist attacks," the Justice Department wrote.

The documents, which were first reported by The Washington Post, were filed in opposition to a request that terror suspect Majid Khan should be given access to an attorney. Khan, 26, immigrated from Pakistan and graduated high school in Maryland.

According to documents filed on his behalf by the Center for Constitutional Rights, Khan was arrested in Pakistan in 2003. During more than three years in CIA custody, Khan was subjected to interrogation techniques that defense attorneys suggest amounted to torture.

President Bush acknowledged the existence of the CIA system in September and transferred Khan and 13 other prisoners designated as "terrorist leaders" to the military prison at Guantanamo Bay, Cuba. Under a law passed last month, they are to be tried before special military commissions and may not have access to civilian courts.

The Center for Constitutional Rights is among several advocacy groups challenging that law. They say the Constitution guarantees prisoners a right to challenge their detention.

The Justice Department argues that civilian courts no longer have jurisdiction to intervene in the case. They say keeping details about the CIA program secret is essential because national security is at stake.

"Information obtained through the program has provided the United States with one of the most useful tools in combating terrorist threats to the national security," the government argued in court documents.

"It has shed light on probable targets and likely methods for attacks on the United States, has led to the disruption of terrorist plots against the United States and its allies, and has gathered information that has played a role in the capture and questioning of senior al-Qaida operatives," it said.

Gitanjali S. Gutierrez, an attorney with the Center for Constitutional Rights, responded in court documents Friday that there is no evidence Khan has classified information. Gutierrez accused the administration of using national secrecy concerns to "conceal illegal or embarrassing executive conduct."

U.S. District Judge Reggie B. Walton has not indicated when he will rule.