GUANTANAMO BAY NAVAL BASE, Cuba - Defense Secretary Donald H. Rumsfeld yesterday ruled out any possibility of granting prisoner of war status to the suspected terrorists held in a makeshift prison on this U.S. Naval Base.

"They are not POWs. They will not be determined to be POWs," Rumsfeld told reporters accompanying him on his first visit to the detention facility.

The Bush administration considers the captured fighters to be "unlawful combatants" and "detainees" because their method of terror violates internationally accepted laws and specifically targets civilians.

The distinction is significant because under the Geneva Convention, written after World War II, a POW has certain legal rights that would govern the U.S. military's interrogations of the detainees and would require that they be released when the hostilities in Afghanistan are over.

If there is any ambiguity about whether a captive should be considered a prisoner of war, the Geneva Convention says a special three-person military tribunal should be convened to decide.

Rumsfeld said that is irrelevant at Guantanamo Bay.

"There is no ambiguity in this case," he said.

Vice President Dick Cheney said yesterday that officials agree the detainees aren't prisoners of war. But administration lawyers are debating whether the Geneva Convention, which has provisions that deal with unlawful combatants, applies in this case.

"These are the worst of a very bad lot," Cheney told "Fox News Sunday. "They are very dangerous. They are devoted to killing millions of Americans, innocent Americans, if they can, and they are perfectly prepared to die in the effort. And they need to be detained, treated very cautiously, so that our people are not at risk."

The detainee issue is likely to come up today at the regularly scheduled National Security Council meeting, which President Bush attends, a senior administration official said.

Rumsfeld and Gen. Richard Myers, chairman of the Joint Chiefs of Staff, traveled to the detention facility, known as "Camp X-Ray," by plane, boat and bus, accompanied by four senators: Democrats Dianne Feinstein of California and Daniel Inouye of Hawaii, and Republicans Ted Stevens of Alaska and Kay Bailey Hutchison of Texas.

They came to get a firsthand look at the facilities and procedures used in handling the 158 prisoners being detained in 8-by-8 foot, open air cells.

As military workmen pounded away, building new holding cells in the distance, Rumsfeld walked through an area of the camp and got to see many of the detainees in their cells.

Last week, Rumsfeld halted the transfer of prisoners from Afghanistan, citing a shortage of cells. On yesterday, he said he was considering when to begin building more permanent facilities.

Rumsfeld said the purpose of the trip was not to investigate the treatment of the captured al-Qaida and Taliban fighters, although some U.S. allies have raised questions about it. He said he came mainly to thank the U.S. troops guarding the prisoners and to meet with their commanders.

"I have absolutely full confidence in the way the detainees are being handled and treated," Rumsfeld said. "It is a tough job," he added, noting that al-Qaida has vowed to kill Americans anywhere and wherever possible. The United States blames al-Qaida and its leader Osama bin Laden for the Sept. 11 terrorist attacks on the World Trade Center and the Pentagon.

"These are among the most dangerous, best trained, vicious killers on the face of the earth."

Rumsfeld said there has been a lot of misinformation and confusion about the handling of the prisoners and distortion of the conditions under which they are living here.

Last week, the Defense Department released a photograph of some of the prisoners in manacles, kneeling and wearing goggles and ear muffs. That triggered protests in Europe and elsewhere about the conditions at Guantanamo Bay.