WASHINGTON -- The Defense Department announced Tuesday it transferred two detainees from Guantanamo Bay, Cuba, to the Belgian government.

So far, 234 detainees have left Guantanamo. In addition to the 18 announced Tuesday, 149 have been released outright and 67 transferred to the control of other governments: 29 to Pakistan, five to Morocco, nine to Great Britain, seven to France, seven to Russia, four to Saudi Arabia, two to Belgium, and one each to Spain, Sweden, Kuwait and Australia.

The Combatant Status Review Tribunal process was conceived by the Pentagon last year in response to a Supreme Court ruling that said prisoners could challenge their detention in court. The Pentagon hopes the tribunals will be accepted by the courts as meeting the Geneva Convention requirement for neutral hearings to determine the status of military prisoners.

The military freed 18 prisoners a week ago without charges -- 17 from Afghanistan and one from Turkey.

There are now approximately 520 prisoners at Guantanamo, which was created to house prisoners taken in the global war on terror. Some prisoners have been held since January 2002.