(AP) The U.S. government is preparing to free a small number of prisoners from its high-security jail in Cuba, in what would be the first release of combatants who are no longer considered a terrorist threat.

"There are some people likely to come out of the other end of the chute," said Defense Secretary Donald Rumsfeld, at a Pentagon press conference Tuesday.

Other officials said on condition of anonymity that it could be within days.

Rumsfeld said officials are vetting the prisoners to make sure they are not candidates for prosecution, no longer of any intelligence value, and not a threat to the United States or its allies.

The first batch to be let go will be "a relatively small number" of men, he said, adding that he didn't know their nationalities.

Pakistani officials have said a visit to the prison turned up a number of Pakistanis who do not represent a threat to the United States.

The government, a major U.S. ally in the counter-terror war, has asked the men to allowed to return to Pakistan. It's unclear how many other countries have sought release of their nationals.

"We vetted them and gave our assessment ... that some of the detainees did not pose a threat" to the United States, said Asad Hayauddin, spokesman for the Pakistan Embassy in Washington.

There are reported to be some 58 Pakistanis in Guantanamo, 100 Saudi Arabians, a dozen Kuwaitis and so on. In all, the United States is holding 598 men from 42 countries who it has labeled as enemy combatants, saying it may legally hold them until the end of hostilities. It hasn't made clear whether that means the end of the campaign in Afghanistan or the entire global war which is expected to go on for years.

It is not clear whether the men to be released will be freed completely or simply transferred to some other country for detention, Rumsfeld said.

The U.S. government has said for months that some of the prisoners might eventually be prosecuted, released to other countries for prosecution or held indefinitely.

Though rules for military tribunals were announced nearly seven months ago, no one has been ordered sent before a tribunal for trial.

Some of the men have been held for nearly a year since being rounded up during the air war that opened the military campaign in Afghanistan on Oct. 7. Transfers from Afghanistan to Guantanamo began in January.

The main task with them over the months has been to interrogate them for information that might help prevent future attacks and catch other suspects, officials have said.

"Over the course of our efforts against terrorism, we expect there will be numerous releases, and presumably transfers, to other countries," Pentagon spokesman Lt. Cmdr. Jeff Davis said, declining to give further detail.

One official said that for safety reasons, no transfer will be announced until the prisoner or prisoners have safely arrived wherever they are being sent.

Officials fear al Qaeda will track down anyone who is released and try to get information from them, forcibly if need be, on such things as U.S. interrogation methods, security procedures, details of other detainees and any potential weaknesses in security at Guantanamo.

Up until now, transfers into Guantanamo have been one-way trips for the vast majority of prisoners. The only ones acknowledged sent out by the U.S. government so far have been a man with mental health problems and prisoners determined to be Americans, who were sent for detention in the states instead.