The war crimes tribunal for the Guantanamo prisoner charged in the attack on the USS Cole is going into a closed session dealing with a subject so secret even the defendant can't hear it.

The judge hearing pretrial arguments in the case of Abd al-Rahim al-Nashiri rejected defense arguments that he be permitted to sit in on the hearing. Army Col. James Pohl did not rule out allowing al-Nashiri to attend future closed sessions. But Pohl ruled Thursday that the upcoming session would be sensitive enough to exclude him for reasons of national security.

The subject of Friday's closed hearing has not been disclosed.

Al-Nashiri faces charges that include terrorism and murder for orchestrating the al-Qaeda attack on the Cole in 2000, an attack that killed 17 crew members.