WASHINGTON - The U.S. military on Monday flew about 30 new detainees in the war on terror to the U.S. Navy base in Guantanamo Bay, Cuba, after releasing four who had been held there, leaving about 625 imprisoned, the Pentagon said.

Defense Department spokeswoman Victoria Clarke refused to say exactly how many had arrived or where they had been flown from. But the total held before the release of four suspected al Qaeda and Taliban prisoners on Saturday had been 598.

"This morning, a number of new detainees arrived, bringing the number to approximately 625," Clarke said. The four were released after the Pentagon determined they were of no further intelligence value, she added.

It was the first arrival of prisoners at the base since Aug. 5, when 34 were flown to Guantanamo. Detainees began arriving there under heavily armed guard from Afghanistan and other areas in January and are being held at a prison camp built for them after the devastating Sept. 11, 2001, attacks on America.

The prison facility is currently being expanded to hold up to 816 people. No charges have been filed against any of the detainees although the Bush administration has left open the possibility some could face military tribunals.

'PLANNING TO RELEASE MORE'

Clarke declined to identify those released. But Pakistani officials in Islamabad said one had arrived there Sunday.

"We are definitely planning to release more," said Clarke.

"For operational security reasons, we're not talking about where they're from or where they're going."

The Pentagon announced last week after months of interrogation the United States planned to release some of the "detainees" from 43 countries who were no longer of intelligence value or candidates for prosecution in the war on terrorism declared by President Bush after last year's attacks.

Pakistan's government said that the first of its citizens had arrived overnight in Islamabad from U.S. custody and more would coming in the near future.

A Pakistani official said Muhammad Sagheer arrived in Islamabad on Sunday night. State-owned television said authorities were expecting 13 more Pakistani prisoners to be released, but did not say when.

Pakistan said last month the majority of its 58 citizens detained at Guantanamo were not linked to the al Qaeda network of Osama bin Laden, blamed for the attacks on the United States.

One Afghan prisoner was repatriated from Guantanamo to Afghanistan in April after doctors determined he was mentally ill.

The only other prisoner moved from the camp until now was Yaser Esam Hamdi. He was sent to a Navy prison in Norfolk, Virginia, after authorities learned he was born in Louisiana to Saudi parents and could be considered a U.S. citizen. He is being held there indefinitely as an "enemy combatant."

Pakistani television reported the aircraft that brought Sagheer to Pakistan stopped en route at Bagram air base in Afghanistan, where it dropped off some Afghans released from Guantanamo.

Bagram is the headquarters of the U.S.-led coalition in Afghanistan.