A U.S. military judge is considering broad security rules for the war crimes tribunal of five Guantanamo prisoners charged in the Sept. 11 attacks, including measures to prevent the accused from publicly revealing what happened to them in the CIA's secret network of overseas prisons.

Prosecutors have asked the judge at a pretrial hearing starting Monday to approve what is known as a protective order that is intended to prevent the release of classified information during the eventual trial of Khalid Sheikh Mohammed, who has portrayed himself as the mastermind of the terror attacks, and four co-defendants.

Lawyers for the defendants say the rules, as proposed, will hobble their defense. The American Civil Liberties Union, which has filed a challenge to the protective order, says the restrictions will prevent the public from learning what happened to Mohammed and his co-defendants during several years of CIA confinement and interrogation.

The protective order requires the court to use a 40-second delay during court proceedings so that spectators, who watch behind sound-proof glass, can be prevented from hearing — from officials, lawyers or the defendants themselves — the still-classified details of the CIA's rendition and detention program.