The U.S. government will decide in good time what to do with an American believed to have been fighting alongside the Taliban, Defense Secretary Donald H. Rumsfeld said Tuesday.

He declined to say whether he considered the man a traitor.

"We found a person who says he's an American with an AK-47 in a prison with a bunch of Al Qaeda and Taliban prisoners," Rumsfeld told a Pentagon press conference. "You can be certain he will have all the rights he is due."

U.S. and allied Afghan forces are holding three former Taliban fighters who claim to be American citizens. One of them, an injured man who identified himself as John Walker, is receiving medical treatment from U.S. forces after emerging from a battle-scarred fortress in Mazar-e-Sharif.

Walker, 20, who converted to Islam when he was 16, suffered grenade and bullet wounds, according to one broadcast report. His parents identified him from video and photographs as John Philip Walker Lindh of Fairfax, Calif.

Asked if he had considered what to do with the man, Rumsfeld said Walker is not the No. 1 priority right now.

"We'll get to that in good time," Rumsfeld said.

"I do know a bit about the various options and I have not landed on one at the moment," he said. "I've got lots of things that are front and center that we're dealing with at the time."

Pentagon spokeswoman Victoria Clarke said earlier that American officials have been talking with Walker.

Walker's father, Frank Lindh, said he has hired a lawyer and wants to visit his son, who had studied Arabic and Islam in Yemen and Pakistan. "We're anxious to hear from the government," he said Tuesday on NBC's Today show.

On Monday night, Lindh said it appeared his son had been a combatant with the Taliban. "He's really not much more than a boy," he said.

"We want to give him a big hug. I also want to give him maybe a little kick in the butt for not telling me what he was up to and for not getting my permission, because I would not have given him permission to go to Afghanistan."

Two other people who claim to be Americans are under the control of the Northern Alliance, a defense official said, speaking on condition of anonymity. The official knew few details about these two, whose identities have not been established and whose physical condition could not be determined.

Asked about Walker, Rear Adm. John Stufflebeem, the deputy director of operations for the Joint Chiefs of Staff, could not say Monday whether Walker is considered a prisoner of war or whether he would be returned to the United States.

"The only thing that I can say about this individual is that this is somebody who claims to be an American citizen," he said. "That claim is being respected for the moment, until facts can be established."

Lindh said he was concerned about some statements his son reportedly made supporting the Sept. 11 terrorist attacks and the Taliban's resistance to the U.S. anti-terrorism campaign.

"I don't know of any information that he's done anything wrong," Lindh said. "I hope he could be debriefed and come home."

The U.S. government could find it difficult to successfully bring criminal charges against Americans fighting for the Taliban.

A case against Walker "would be a tricky thing to prosecute because the Constitution requires two eyewitnesses to the act of treason," University of North Carolina law professor Eric Muller said. "I would think somebody in the Justice Department will have to take a very careful look at this." Also, President Bush's military tribunals are limited to foreign nationals, not U.S. citizens.

Another possible avenue would be to charge American Taliban fighters with seditious conspiracy, which has a lower standard of proof. That's one of the charges that radical Islamic cleric Omar Abdel-Rahman, who plotted to blow up New York City landmarks, was convicted on in 1995. One of Abdel-Rahman's sons was captured while fighting for the Taliban in Afghanistan.