Incensed that two guards stripped a detainee of his turban during prayer, nearly two-thirds of the prisoners captured in the Afghan war refused lunch Thursday and chanted "God is great" in Arabic in their first mass protest since arriving at the base.

In addition, some detainees pushed sheets, blankets, sleeping mats and other items through the small openings in the chain-link walls of their cells in protest, Marine Maj. Stephen Cox, the detention mission spokesman, told reporters.

Thursday night, Brig. Gen. Mike Lehnert, the Marine general running the detention mission, used the camp loudspeaker to tell inmates they would be allowed to wear turbans. Cox said, "We will reserve the right to inspect [turbans] at any time."

Cox reported that Lehnert promised the military would respect detainees' religion and the Quran, the Muslim holy book.

Afterward, reporters could see several detainees wearing turbans fashioned from white bed sheets. Eighty-eight detainees refused their evening meal Thursday night even after Lehnert's address, Cox said.

Tension has been building among the 300 inmates who have been held at Camp X-ray, the remote U.S. naval base in eastern Cuba, since January.

In recent days, some have been ignoring a taped call to prayer and instead have picked individual detainees to announce and lead prayer, which Muslims do five times a day.

Cox said Lehnert spoke with the captives to address some of their concerns.

"He told them at this point he could not to tell them how long they will be here or what will happen to them in the future," Cox said. But "Gen. Lehnert also told the detainees that they will be judged fairly" when the time comes.

The detainees told a duty officer their protest was in response to an incident that took place Tuesday, Cox said. A detainee had fashioned a turban out of a sheet and was wearing it on his head during prayer. Two military guards ordered the inmate to remove the turban, but the inmate ignored the order, he said. Even after a translator repeated the same order, the inmate refused to acknowledge it.

The guards shackled the inmate and then stripped off the turban, Cox said.

"We don't allow fashioning of a headdress that would allow them to shroud any type of item or weapon," he said. The detainees have been issue prayer caps or can drape towels over their heads, Cox said.

He said 159 detainees skipped lunch and 109 skipped dinner on Wednesday. On Thursday, 107 skipped breakfast and 194 refused lunch.

Medical personnel have been monitoring the detainees and are prepared to feed them intravenously if needed, Cox said.

Cox said the protest appeared to be about more than just the turban, but inmates have made no demands.

Amnesty International said the protest "highlights the dangers of the legal limbo into which the prisoners have been thrown.

"This latest development underscores the urgent need for the United States to acknowledge that all of the prisoners are covered by the Geneva Conventions, and to ensure that they are granted due process rights, including the right to challenge their continued detention," Amnesty spokesman Alistair Hodgett said in Washington.

The military says the prisoners are fighters of the international Al Qaeda terrorist network and the deposed Afghan Taliban regime that harbored it.

U.S. officials say they are determining whether and how to prosecute the men, and that those not tried by a military tribunal would either be prosecuted in a U.S. court, returned to their home countries for prosecution, released outright or held indefinitely.

Officials say the men pose a danger not only to the troops but also to themselves. Some Islamic groups preach that dying in a holy war guarantees a place in heaven — the mantra of suicide bombers in Israel and that of the hijackers who flew passenger jets into the World Trade Center towers and the Pentagon on Sept. 11.