GUANTANAMO BAY NAVAL BASE, Cuba -- About 75 captives of the war on terrorism held to a hunger strike for a fourth day Saturday in a protest rooted in uncertainty over their indefinite detention and their fate, a U.S. military commander said.

Six detainees have been given liquids with an intravenous drip, one against his wishes, officials said.

"Right now, we have a hunger strike of about 75 hard-liners, with a number of sympathy strikers joining in periodically," said Brig. Gen. Michael Lehnert, commander of the detention mission at this U.S. naval base in southeastern Cuba.

A large group among the 300 detainees stopped eating Wednesday, some telling their captors they were upset that a guard stripped a detainee of his turban during prayers on Tuesday.

But Lehnert said that while the turban issue was one cause, the "underlying complaint" was concern about the future.

"The single biggest complaint is that they want to know what will happen to them," he said.

Prosecution decisions

U.S. officials say they are determining whether and how to prosecute the men and that those not tried by a military tribunal would be prosecuted in U.S. courts, returned to their home countries for prosecution or released outright. They could also be held indefinitely, Defense Secretary Donald H. Rumsfeld has said.

The prisoners -- whom the U.S. military says belong to the international al-Qaida terrorist network and Afghan-istan's fallen Taliban regime -- are being interrogated and are not allowed lawyers.

On Saturday, 85 detainees refused to eat breakfast and 73 wouldn't eat lunch, down from a high of 194 who declined lunch Thursday. Fewer than 10 were refusing to drink fluids, Lehnert said.

By Saturday afternoon, Marine Maj. Stephen Cox said, six detainees had been treated for dehydration with intravenous drips at the camp infirmary.

"Five of the six agreed to the IV. There was one individual who did not want the IV," Cox said. "We overrode his desire and administered the IV."

It is the first mass protest since the initial group of detainees was flown to Guantanamo on Jan. 11. Some of the inmates were held for months in Afghanistan before they arrived.

The hunger strike began after two military guards shackled an inmate and stripped off his turban during prayers Tuesday, after he ignored repeated orders to take it off. The detainees also have been issued Muslim prayer caps and copies of the Quran.