The U.S. military has removed journalists from a Guantanamo courtroom for a secret session of the war crimes tribunal.
It is the first time the U.S. has held a closed session at the tribunals created to prosecute alleged terrorists at the base in Cuba.
Observers without security clearance were told to leave Thursday while a defense witness testified in the trial of former Osama bin Laden driver Salim Hamdan.
The defendant stayed in the courtroom.
The witness is Col. Morgan Banks, a psychologist with the U.S. Army Special Operations Command. Officials did not say why his testimony is being kept secret.
AP