U.S. military authorities have begun the process of transfering Taleban and al-Qaida detainees from Afghanistan to the American naval base at Guantanamo Bay in Cuba.

The first batch of detainees were seen hooded and chained as they assembled at Kandahar airport under heavy guard for the flight to Cuba. Some reports said they may have been sedated for the lengthy trip.

Defense Secretary Donald Rumsfeld said only that appropriate restraint is being used. He defended the extraordinary security precautions in place for the transfer, calling some of the detainees dangerous people. "There are among these prisoners people who are perfectly willing to kill themselves and kill other people," he warned.

Mr. Rumsfeld noted Taleban and al-Qaida detainees were involved in a bloody prison uprising in Mazar-i-Sharif. Others were involved in a shoot-out with Pakistani guards. Still another blew himself up.

During an exchange with Pentagon reporters following a meeting with Australia's visiting defense minister, Mr. Rumsfeld also paid tribute to the seven US military personnel killed in the crash of their tanker aircraft in Pakistan.

He said there is no indication of any hostile fire or foul play in the incident, but he said the latest deaths underscore the dangers of the anti-terrorism campaign. "The mission in Afghanistan remains difficult and remains dangerous. We have said that repeatedly," he explained. "It is a fact, and it will continue to be a fact during the weeks and months ahead."

Meanwhile, Mr. Rumsfeld is declining to discuss intelligence information the United States reportedly has about possible links between al-Qaida terrorists and Iran. But he noted Iran is on the US list of state sponsors of terrorism, that it neighbors Afghanistan and that there has been movement across in the border in recent times. "I would prefer that countries not harbor terrorists and that countries not provide haven for al-Qaida and that they not support terrorist networks," he said.

On another issue, Mr. Rumsfeld confirmed more US troops are helping in the training of anti-terrorism forces in the Philippines. He said the government there is attempting to deal seriously with the problem posed by terrorists who have in some cases seized hostages.