President Bush has designated nine additional prisoners at Guantanamo Bay, Cuba, as subject to military tribunal, the Pentagon said Wednesday.

The nine have not been charged and were not identified by military officials, nor have any tribunals been scheduled. They join six others at Guantanamo (search) whom Bush had previously designated as eligible for military tribunal (search).

"The president determined that there is reason to believe that each of these enemy combatants was a member of Al Qaeda (search) or was otherwise involved in terrorism directed against the United States," the Pentagon said in a statement.

The nine may have attended terrorist training camps, provided financing for Al Qaeda, planned maritime terrorist attacks, made explosives or been a bodyguard for Usama bin Laden (search), the Pentagon alleged.

The announcement came as the Bush administration works to determine the fates of the roughly 595 people held at Guantanamo, some for longer than two years. Most were captured on the battlefield in Afghanistan, and their long, seemingly indefinite detention at the naval base has drawn criticism from human rights groups.

Last week, the Supreme Court ruled that these prisoners had the right to challenge their detention in a U.S. court, but the logistics of such hearings have not been worked out.

Prisoners will also have the right to present a case to a panel of military officers to secure their release.

Of the 15 people now designated for military tribunals, only three have been identified and charged: David Hicks of Australia, Ali Hamza Ahmad Sulayman al Bahlul of Yemen, and Ibrahim Ahmed Mahmoud al Qosi of Sudan.

Hicks was a cowboy who converted to Islam and fought alongside the Taliban in Afghanistan, the military alleges. Al Bahlul was a bodyguard and communications expert, and al Qosi worked as an Al Qaeda accountant and later served as bin Laden's bodyguard, driver and cook, it charges. None of the three is specifically accused of killing Americans.

The Pentagon has announced a five-member tribunal would try the three suspects at Guantanamo. The trials would be the first convened by the United States in nearly 60 years.

The presiding officer of the tribunal will be Army Col. Peter E. Brownback III, who has 22 years of experience as a judge advocate and nearly 10 years of experience as a military judge, the military said.

It said the remaining panel members are two U.S. Marine Corps colonels, an Air Force colonel and an Air Force lieutenant colonel, but did not identify them by name.

Military tribunals are reserved for foreign-born captives and have lower standards for prosecution than in American civilian courts, and prosecutors typically have a smaller burden for proving guilt than beyond a reasonable doubt. Some evidence also might be withheld from the defendant — but not the military judges — if the information is deemed classified.

Defense lawyers have criticized the military tribunal process as stacked against them. Britain's attorney general has said that military tribunals were unacceptable because they would not provide a fair trial by international standards.