The FBI director, Robert Mueller, and a former attorney general, John Ashcroft, must decide whether to challenge yesterday’s federal appeals court ruling affirming one Muslim man’s right to bring a suit against them alleging that he was abused during his detention following the September 11, 2001, terrorist attacks.

Javaid Iqbal, a Pakistani immigrant, says Messrs. Ashcroft and Mueller approved the harsh treatment that he says he experienced during his captivity and that they did so based on his religion, race, or national origin.

Mr. Iqbal spent months at a Brooklyn prison, along with dozens of other New York-area Muslim immigrants whom the government considered “of high interest,” until he was cleared of any terrorism connection and deported. Mr. Iqbal says prison staff kept him in solitary confinement and denied him medical care, adequate meals, possession of a Koran, and communication with his attorney. He also said they brutally beat him and left the lights on in his cell for 24 hours a day.

A three-judge panel for the U.S. Second Circuit Court of Appeals denied the claim made by Mr. Ashcroft and the other government officials that they were legally immune from the suit based on national security concerns.

“This is unprecedented. This case is basically trying to hold the highest federal officials of our government accountable for what happened,” said Haeyoung Yoon of the Urban Justice Center, which represented Mr. Iqbal.

If the government decides to challenge the ruling, it can ask the entire Second Circuit to rehear the case or appeal to the Supreme Court of the United States. The Justice Department is currently studying the decision, a department spokesman said.