U.S. military authorities have released four prisoners who had been held for months at the Navy detention facility in Guantanamo Bay, Cuba, and will release others soon, officials said.

The four -- three Afghans and a Pakistani -- constitute the first group to be released from the prison since it began housing detainees captured abroad in January. But even as the four were being flown back to their home countries over the weekend, another group of about 30 new captives was flown into the detention facility from Afghanistan.

"Senior leadership of the Department of Defense, in consultation with other U.S. government officials, determined that these four detainees no longer posed a threat to U.S. security," chief Defense Department spokesman Victoria Clarke said yesterday at a Pentagon news conference. The men were released Saturday.

U.S. officials declined to release the names or nationalities of the men, but sources in Pakistan identified the freed Pakistani detainee as Mohammed Sagheer, 60, who is from the North-West Frontier Province that borders Afghanistan. Pakistani newspapers reported that officials there said they will debrief Sagheer before releasing him to his family in the town of Mansehra.

Private aid officials confirmed the other three men released were from Afghanistan, but their identities could not be learned yesterday.

U.S. officials said they plan to free small groups of detainees from Guantanamo Bay after determining they have no intelligence value and do not pose a terrorist danger. Until Saturday, the only detainees removed from Guantanamo Bay were a man returned to Afghanistan after it was determined he was mentally ill, and a captive transferred to a U.S. military brig after officials learned he may be a U.S. citizen.

"We have no desire to hold large numbers of these people for a long period of time," Clarke said. "If we can go through all those factors -- determine someone doesn't have [intelligence] value, is not a real threat to the United States or our friends and allies, we think there will be proper handling on the other end -- then we'd like to get rid of some of these people. So we're working a lot of those issues with countries, but it takes time."

U.S. and foreign officials have said about six more of the 55 or so remaining Pakistani inmates in Cuba are expected to be repatriated. During visits to Guantanamo Bay and Washington in August, Pakistani officials told U.S. authorities that a number of the Pakistani men being held appeared to be innocent bystanders swept up in mass arrests near the Afghan-Pakistan border.

The families of 12 Kuwaiti men held at Guantanamo Bay said in a statement that they are "disappointed" that none of their relatives was in this first group of inmates to be let go. But they added in the statement transmitted by their Washington lawyers that "we are encouraged by this first step, and hope the Kuwaitis will be freed soon. The process of releasing innocent people has begun."

There were approximately 598 inmates in Cuba before the four were flown on U.S.-chartered planes to their homelands. The 30 additional detainees flown to Cuba from the U.S. interrogation facility at Bagram brings the total number of prisoners in Cuba to about 624. With the completion of 204 new cells in recent days, the Guantanamo Bay compound can house a total of 816 inmates.

The last time new prisoners were flown into Guantanamo Bay was in early August, when 34 men were delivered there. The largest increase came in June, when more than 200 arrived.