The U.S. government asked a judge Thursday to order the return of a secret document about a detention center in Afghanistan that it mistakenly gave to a civil rights group, saying its release could frustrate military and intelligence-gathering efforts and do serious damage to national security, including interfering with foreign diplomatic relations.

Government lawyers submitted court documents in federal court in Manhattan after the American Civil Liberties Union alerted them to the May 13 release of a document about the criteria for holding detainees at the Bagram detention center that was marked secret. The ACLU wants the court to declare that the document should never have been classified and open it up to public debate, while the government wants it returned and kept secret.

To support its argument, the government submitted a declaration by William K Lietzau, a deputy assistant secretary of defense, who said Department of Defense personnel in Afghanistan have expressed concerns that public release of criteria used to decide how to classify detainees could have significant harmful repercussions for U.S. diplomatic relationships with Afghanistan and other countries.

"The current fight against violent extremism is not limited to the battlefield," Lietzau wrote. "Arming enemy forces with the information they need to avoid an accurate threat classification will counter our efforts to segregate the most dangerous detainees from less violent and radicalized detainees in our facilities and ultimately expose both the guard force and other detainees to increased risk of harm."

He said it would be reasonable to assume that public release of criteria would become known to hostile forces and increase their ability to undermine the accuracy of U.S. assessments of a detainee's identity and threat level.

"This could then result in the premature release or transfer of a high-threat individual under conditions not designed to mitigate his threat," he said. "Based on past experience, DOD has learned that insurgents in Afghanistan and elsewhere are able to obtain and synthesize information, including U.S. government information that is publicly available, and can and do adapt their behavior and responses to post-capture interrogations accordingly, with a goal of evading determinations that might result in detention."

The government inadvertently sent two copies to the ACLU of a document that lists the criteria used to determine whether a particular detainee meets the standard to be classified as an "enduring security threat," the highest threat category.

The documents were turned over along with thousands of other pages released in response to an April 2009 Freedom of Information Act request seeking records pertaining to the process for determining and reviewing Bagram prisoners' status, the process for deciding if their detention is appropriate and the process for determining who should be released. The ACLU filed a lawsuit in September 2009 seeking an order to compel disclosure of the documents.

The government said it received a letter from the ACLU on May 25 to say it seemed that the release of the documents might have been by mistake. The documents remain in a locked cabinet while the court decides what to do.

In a release Thursday, the ACLU said it was indefensible that the government still seeks to suppress a document that never should have been secret.

"This is not a document that should be classified. Having seen the document there is nothing about it that could pose a threat to national security if disclosed," Hina Shamsi, director of the ACLU's National Security Project, said in an interview.

She said in a release that the criteria used to hold and classify detainees should be open to public debate and that there is nothing in them that would surprise anyone who has followed the U.S. government's positions on detention and terrorism prosecution in the last 10 years. The ACLU said there were nearly 1,800 people, about triple the number when it filed its lawsuit, detained at Bagram with no meaningful process to challenge detention.


Associated Press Writer Adam Goldman in Washington contributed to this report.