A U.S. federal judge ordered the release of five Algerians held at Guantanamo Bay, Cuba, and the continued detention of a sixth Nov. 20 in a major blow to the Bush administration's strategy to capture and hold terrorism suspects without charges.

A Guantanamo detainee peer from his cell Nov. 18. AP PHOTO

In the first case of its kind, U.S. District Judge Richard J. Leon said the government's evidence linking the five Algerians to al-Qaida was not credible as it came from a single, unidentified source. Therefore, he said the five could not be held indefinitely as enemy combatants and should be released immediately.

"To allow enemy combatancy to rest on so thin a reed would be inconsistent with the court's obligation," Leon told the crowded courtroom.

As a result, "the court must and will grant the petitions, and order their release," he said.

Leon said there was enough reason to believe the sixth Algerian, Belkacem Bensayah, was close to an al-Qaida operative, and had sought to help others travel to Afghanistan to join the terrorists' fight against the United States and its allies.

One of the men to be released is Lakhdar Boumediene, whose landmark Supreme Court case last summer gave the Guantanamo detainees the right to challenge their imprisonment.

The Bosnian government already had agreed to take back the detainees, all of whom immigrated there from Algeria before they were captured in 2001.

Leon urged senior Justice Department leaders and high-level officials at other government agencies involved in the case not to appeal his ruling. The department said it had not decided whether it would.