Updated

Long-term prisoners being held at the naval base at Guantanamo Bay (search), Cuba, will receive annual reviews to determine whether they should remain in custody, Defense Secretary Donald Rumsfeld said Friday, as he defended against charges the lengthy detentions violate human rights.

The reviews will determine whether prisoners, if released, would remain a threat to the United States, officials said.

Many details of the reviews have not been worked out, officials at the Pentagon said. The composition of the reviewing panel has not been decided. The panel will make recommendations, probably to Rumsfeld, who will make the final call on whether to release a prisoner.

Prisoners will receive some kind of assistance, but it has not been decided whether that will include actual lawyers or some sort of military-appointed advisers to explain the process to them, the officials said.

In announcing the reviews, Rumsfeld defended the continued detention of about 650 suspected Al Qaeda and Taliban supporters at Guantanamo. Human rights groups have criticized the treatment of the prisoners as well as their lack of access to lawyers.

"We need to keep in mind that the people in U.S. custody are not there because they stole a car or robbed a bank," Rumsfeld said in remarks to the Greater Miami Chamber of Commerce. "They are enemy combatants and terrorists who are being detained for acts of war against our country and that is why different rules have to apply."

Paul Butler, the deputy assistant secretary of defense for detainee operations, told reporters at the Pentagon that the detainees at Guantanamo fall into several categories: ones who are no longer a threat and can be freed, ones who committed war crimes and will face a military tribunal, and ones who remain a threat but cannot be charged with any crime.

Of those who remain a threat, a few are being turned over to the governments of their home countries. So far, four men have been turned over to Saudi Arabia and a fifth to Spain.

"The detainees are not in a legal black hole," Butler said.

The rest will remain at Guantanamo until their status changes, to prevent them from rejoining Al Qaeda or until the end of the war on terrorism — an uncertain condition, Butler said. Rumsfeld said the United States "has no desire to hold enemy combatants any longer than is absolutely necessary."

Some 87 detainees have been released. Butler said the Pentagon was concerned that some may have been working with Al Qaeda since their release.

Many of the Guantanamo prisoners were captured on the battlefields of Afghanistan during the past two years. Officials said some have provided useful intelligence during interrogations while others have not.

Without providing names, Butler said the prisoners include a former bodyguard of Usama bin Laden, operatives linked to the 1998 attacks on U.S. embassies in Africa and the 2000 attack on the USS Cole, (search) a shoe bomb manufacturer and an alleged associate of the Sept. 11 plotters who was denied entry into the United States less than a month before the attack.

The U.S. government calls them all "enemy combatants," not prisoners of war, saying they don't fight according to the Geneva Conventions (search) and therefore are not subject to its protections. Officials have said the lengthy detentions are vital to intelligence-gathering and that the information gleaned from them has led to arrests around the world.

The Supreme Court is expected to decide this year whether the Guantanamo detainees can be held indefinitely without lawyers and hearings.