The military also said five detainees have refused to appear before the tribunals, which determine whether a detainee is properly held as an ''enemy combatant'' or should be released.
Navy Secretary Gordon England visited the U.S. military prison Wednesday to observe the hearings aimed at reviewing the cases of hundreds of prisoners accused of links to Afghanistan's ousted Taliban rulers or al-Qaida terror network.
''It is very professional. It is very rigorous. I believe it is very fair,'' England said after attending a hearing where a detainee was present.
Human rights groups criticize the process as a sham, saying the three officers assigned to hear cases can't be considered impartial and that each detainee should be allowed a lawyer.
Three Yemenis, one Saudi and one Moroccan have refused to participate in the review tribunals since Monday, said Lt. Chris Servello, a spokesman. He said a 29-year-old Yemeni - allegedly a Taliban fighter - was the latest to refuse Wednesday, but the hearing went on without him.
Two others - a 24-year-old Algerian and 24-year-old Yemeni - appeared before tribunals Friday and Saturday. The Yemeni summoned a detainee to testify that he was forced into being a fighter, officials said. The military contends the Yemeni went to Afghanistan to fight, trained at a camp and signed an oath to bin Laden.
The Algerian has said he would kill Americans if released, said Navy spokeswoman Cmdr. Beci Brenton.
Journalists have been barred from attending the tribunals since they began Friday and have not been able to independently verify information. Reporters will be allowed inside starting today, but the military is reserving the right to bar classified portions and is prohibiting the release of prisoners' names.
The first detainees who faced review hearings have not been charged and have been at Guantanamo for more than two years, officials said.
Recommendations by the three-member review tribunals have yet to be announced.
All the approximately 585 detainees at Guantanamo have been deemed ''enemy combatants'' and not prisoners of war under the Geneva Conventions, which would grant them additional legal rights.
The military announced review tribunals after the U.S. Supreme Court ruled in June that prisoners have a right to challenge their detention in U.S. courts.
