The bombs were falling again Saturday as U.S. warplanes bombarded another suspected Taliban building in eastern Afghanistan, while the population of a makeshift prison doubled with suspected Taliban and Al Qaeda detainees.

More than 60 prisoners were swapped Friday from the hands of Afghan fighters who caught them to U.S. Marines operating a makeshift holding center at the Kandahar airport in the south of the country, the Pentagon said.

The transfer doubled the number held in Kandahar to 120. There are more than 130 suspects now being held in U.S. custody, Pentagon officials said.

American John Walker Lindh is among eight other prisoners who are being held on the amphibious assault ship USS Peleliu in the Arabian Sea. They could be candidates for a U.S. military tribunal, which President Bush has authorized to judge and sentence terrorists who are not American citizens.

More Taliban and Al Qaeda detainees are expected to arrive daily at the Kandahar airport base over the next several days, the Pentagon said.

Meanwhile, in the first air strike since Wednesday, American forces bombed a building in the village of Shekhan in eastern Paktia province, a senior defense official said on condition of anonymity.

He said the building was believed to be used by Taliban leadership, but there was no assessment yet of the strike.

The air portion of the war has wound down to only occasional strikes since Afghan fighters in conjunction with U.S. bombing raids drove out former Taliban rulers and Usama bin Laden's Al Qaeda terrorist network from most of the country.

U.S. forces in 2001 "successfully fought a new kind of war ... to rout a new enemy," Bush said during his weekly radio address Saturday.

"The lessons we learn in Afghanistan will guide our military to the future, and make our country stronger and more secure," he said.

U.S. Marines at the Kandahar base were planning to leave, with Army and possibly Air Force personnel expected to arrive soon to replace them, defense officials said. The Marine expeditionary units sent in to establish bases in Afghanistan have done so in Kandahar and to the south at a place they call Camp Rhino — and in the coming weeks the job will be turned over to other troops, officials said.

Afghan fighters hold thousands captured during their sweeping advance across former Taliban territory in the past two months. Pakistan also holds hundreds of prisoners, most captured as they fled the bombardment of Al Qaeda hide-outs in Afghanistan's Tora Bora area.

Afghan and Pakistani authorities have been sifting through their captives, looking for leaders of the radical Islamic Taliban militia and the Al Qaeda terrorist network.

Prisoners that the United States wants to question or possibly bring to trial are being sent to Kandahar, the defense official said. Marines have expanded the facility there to hold about 250 detainees.

CIA and FBI agents are among Americans who have been interrogating prisoners to learn bin Laden's whereabouts, to determine who should be brought to trial and to try to get information about other terrorists or planned terrorist attacks.

A draft of proposed rules for the tribunals states that a unanimous vote of a tribunal's military officers would be required to impose a death sentence on a foreign terror suspect, a U.S. official said Friday on condition of anonymity.

Bush defended the tribunal proposal, saying terrorist suspects would be treated much more fairly than the victims of the Sept. 11 terrorist attacks. Bin Laden and his Al Qaeda network are the major suspects in the attacks.

Bush didn't comment on details of the proposal, saying it is preliminary.

"Whatever the procedures are for the military tribunals, our system will be more fair than the system of bin Laden and the Taliban," he told reporters at his ranch in Crawford, Texas.

Civil rights groups and some members of Congress have said they were concerned about the fairness and openness of the tribunal process.

Pentagon spokeswoman Victoria Clarke said the proposed rules were "a work in progress" being drawn up by the Defense and Justice departments, the White House and National Security Council.

The Associated Press contributed to this report.