The Defense Department is making procedural changes for upcoming military trials of terrorism suspects at Guantanamo Bay (search) to give them additional defendant rights, department officials said Wednesday.

The Pentagon (search) has been criticized by some for overly restrictive procedures that put suspects at an unfair disadvantage.

Air Force Brig. Gen. Thomas L. Hemingway (search), the senior overseer of the trials, which the Pentagon calls military commissions, was scheduled to explain the procedural changes at a Pentagon briefing Wednesday afternoon.

Defense officials, speaking on condition of anonymity because they were not authorized to discuss details in advance of Hemingway's briefing, said Guantanamo Bay defendants will be given extra rights to attend their trials and to see evidence against them. One official said there would be many other changes as well.

The changes were first reported by the Wall Street Journal on Wednesday.

Initial trial proceedings began last August at Guantanamo Bay but the process was suspended last November after a federal judge ruled that the trials violated prisoners' rights under the Geneva Conventions.

More than 500 prisoners are being held at the Guantanamo Bay prison compound. Many were captured in Afghanistan in the months following the U.S. invasion in October 2001, and some have been there since the detention compound was opened in January 2002.

Only four prisoners have been charged with war crimes.