Miami ? Some prisoners at the U.S. camp for terrorism suspects at Guantanamo Bay, Cuba, aren’t guilty of war crimes but are still a threat to national security and must remain imprisoned there or in their home countries, Defense Secretary Donald H. Rumsfeld said Friday.

Rumsfeld didn’t say how long the detentions might continue. But he said the Pentagon intended to create a panel to review prisoners’ cases annually, implying that some detentions might go on for years. Rumsfeld also said the United States was negotiating with some countries in hopes of sending some of the detainees home.

“For those who continue to be a threat but are not guilty of war crimes, the U.S. government would prefer to transfer them to their native countries for detention and for prosecution,” Rumsfeld said. “We are negotiating agreements with a number of countries to facilitate such transfers.”

It was the first public statement by a Bush administration official that suspected terrorists could face indefinite detention without trial. It came as part of a public relations push to defend the detentions weeks before the U.S. Supreme Court will hear arguments challenging their legality. In Washington, senior Defense Department officials had a special briefing to defend the detentions.

Rumsfeld’s comments and the proposed review panel drew criticism from human rights groups, which have been sharply critical of the U.S. refusal to declare the detainees prisoners of war under the Geneva Conventions.

The United States is keeping 650 prisoners from 44 nations in Cuba, most captured in Afghanistan. Only four have received lawyers so far, suggesting they might face war crimes trials.