Five of the seven U.S. Marines who perished when their aircraft crashed have been found by military investigators and are being flown home, a military spokesperson said Saturday.

The Marine KC-130 refueling tanker slammed into a mountain Wednesday and exploded near an air base at Shamsi, in southwestern Pakistan, becoming the single most deadly incident in the anti-terrorism campaign in Afghanistan, which began Oct. 7.

The cause of the crash is still being investigated, but military officials have said they have not found any evidence of hostile fire.

A team of investigators continued to scour the crash area Saturday for the remains of the other two Marines and clues to the cause of the crash, said Maj. Brad Lowell, a spokesman for U.S. Central Command headquarters in Tampa, Fla.

The recovered Marines' bodies will be flown to Dover Air Force Base in Delaware, and should arrive there by Sunday or Monday, Lowell said.

U.S. warplanes struck a huge Al Qaeda training complex in eastern Afghanistan Friday, acting on clues that more members of the terrorist network had arrived there, Lowell said.

The airstrikes hit buildings and caves in the Zawar Kili area, several mountainous square miles near the Afghan city of Khost, near the Pakistan border. American B-52, F/A-18 and B-1B planes dropped bombs on the area, Lowell said.

A U.S. AC-130 gunship also joined the attacks, Lowell said. Those low-flying planes use rapid-fire cannons and mortars and are often deployed against vehicles and buildings the military believes contain enemy forces.

"We do have information that the training camp had been reoccupied by members of Al Qaeda," Lowell said.

Defense Department officials had said Friday they believed Al Qaeda had abandoned Zawar Kili after days of repeated U.S. airstrikes.

Meanwhile, U.S. forces released one prisoner in Afghanistan after determining he "was of no value," Lowell said. The man was set free and not turned over to Afghan or other authorities, Lowell said.

That brought the number of detainees in U.S. custody in or near Afghanistan to 444. Most of them, 391, were at the U.S. base in the southern Afghan city of Kandahar. Another 52 were being held at the air base in Bagram, north of Kabul, the capital.

John Walker Lindh, the American captured while fighting with the Taliban in Afghanistan, remained imprisoned aboard the USS Bataan in the Arabian Sea.

Twenty more Al Qaeda and Taliban prisoners are incarcerated at Guantanamo Bay Naval Station in Cuba.

Interrogations of the detainees and searches of former Taliban and Al Qaeda sites in Afghanistan have yielded information that helped authorities break up alleged Al Qaeda terrorist cells in Singapore and elsewhere, officials said Friday.

Singapore's government said a videotape and other Al Qaeda material found in Afghanistan helped it thwart plans to blow up Western embassies, U.S. Navy vessels, a shuttle bus carrying American military members and the offices of U.S. companies.

Gen. Richard Myers, chairman of the Joint Chiefs of Staff, said the videotape given to the Singaporean government was not the first indication that American forces were under threat there.

U.S. officials, speaking on condition of anonymity, said several countries besides Singapore had used information gathered in Afghanistan to break up Al Qaeda cells. They would not elaborate.

Finding information that could prevent new terrorist attacks is "equally or more important" to the United States than finding Usama bin Laden and his top Al Qaeda commanders, U.S. Defense Secretary Donald H. Rumsfeld said Friday.

U.S. officials are studying intelligence from terrorist bases and prisoners in Afghanistan for clues that could disrupt plans for attacks even deadlier than those on Sept. 11, Rumsfeld said.

Although Al Qaeda leaders no longer can operate effectively inside Afghanistan, U.S. officials have believed since before the military campaign began Oct. 7 that Al Qaeda cells in other parts of the world have attack plans that could be implemented even in bin Laden's absence.

Rumsfeld said prisoners from Al Qaeda and Afghanistan's former ruling Taliban militia told U.S. interrogators that two senior Taliban leaders were killed weeks ago by American bombs. Rumsfeld said those claims could be "disinformation" from the prisoners, however.

In all, no more than 15 senior Al Qaeda and Taliban figures have been captured or killed, Rumsfeld said.

Rumsfeld gave no indication that the U.S. military was moving closer to finding bin Laden or other senior leaders of Al Qaeda or the Taliban. He said the manhunt would continue, and in the meantime the interrogation of prisoners and the capture of documents were providing vast amounts of new information.

He said the information is being gleaned from "an enormous number of documents and videotapes and computer disks and hard drives and laptops and portable phones and address books and the like."

The Associated Press contributed to this report.