Suspected Al Qaeda and Taliban members were transported by U.S. forces from a northern Afghanistan prison Saturday to a temporary lockdown near the Kandahar airport.

To securely transport the detainees U.S. troops sealed off the prison and at 3:30 p.m. six vehicles, including two large closed trucks left it and drove toward the staging area. The number of prisoners being transported was unclear.

"We're taking them out of here, and taking them down to Kandahar as quickly as we can," said Maj. Joseph Fenty, commander of the forces conducting the operation. "We're primarily looking at detainees that we can use for collecting intelligence."

Military officials on the scene were tight-lipped about the details of the operation, which began Friday. Many U.S. troops, armed with rifles and sporting bulletproof vests, were involved in the mission.

American officials plan to transfer the Kandahar detainees to the U.S. naval base in Guantanamo, Cuba.

The population of detainees held at the temporary prison at the Marine base at Kandahar airport has risen steadily this week. The Pentagon was expecting the additions of many more over the next few days, a defense official said Friday in Washington on condition of anonymity.

U.S. officials in Shibergan said they would take Afghans, not only foreigners, to Kandahar if deemed necessary, Fenty said. He said the servicemen were searching prisoners, doing medical tests and initial intelligence screenings.

"We feel we have an adequate-sized force here to protect ourselves as well as the detainees we have extracted," Fenty said. The prison in Shibergan currently holds 3,000 prisoners, 900 of them foreigners.

Inside, the International Committee of the Red Cross was registering prisoners as the United States conducted its operation.

"We're going to treat these detainees humanely. We're going to provide for their safety," said Capt. Robert Riggle, a military spokesman.

On Friday, Red Cross representatives visited the Kandahar camp, where U.S. officials say 62 prisoners already are being detained.

"They visited the command and several persons, and are satisfied with our procedures," Marine Maj. Chris Hughes said. "With every group (of prisoners) we bring in, there are injured — broken bones, dehydration or malnutrition. And they receive medical treatment throughout."

The detainees, military officials have said, are bound, blindfolded and separated from each other by concertina wire. Calls to International Committee of the Red Cross officials in Islamabad and Kabul went unanswered Saturday.

Maj. Ian Brasure, a legal adviser for the 26th Marine Expeditionary Unit, said the detainees are treated well.

"When we get prisoners, we don't torture them, we don't perform medical experiments on them," Brasure said. "We keep them warm, we keep them fed, we keep the rain off their heads."

When the Navy is able to get running water to the detention facility, the men will be able to bathe. "Our goal is to give them what we have," said Lt. Col. Mark Faulkner, commander of the 26th Marine Expeditionary Unit's service support group.

The prisoners are among the thousands captured by Afghan fighters as they took control of the country from the Taliban militia.

As of Friday afternoon, the defense official said, the number of captured Al Qaeda and Taliban figures in U.S. custody was 70, including eight held on a ship. More can be accommodated in Kandahar, he said, because Marines have expanded the facility there to hold some 250.

The Associated Press contributed to this report.