A military tribunal in the Sept. 11 case is going forward at Guantanamo without any defendants.

All five defendants chose to sit out the hearing for the first time since a military judge ruled that they would not be forced to attend. A Navy official who was not identified for security reasons testified that the five declined to leave their Guantanamo jail cells. She did not say if they gave any reasons.

The final day of a weeklong pretrial hearing continued without them Friday, with lawyers sparring over rules for handling classified evidence.

The five face charges that include terrorism and murder for allegedly planning and helping to carry out the Sept. 11, 2001, hijacking plot. They could get the death penalty if convicted.