It wasn't clear if the men and boys to be transferred from Guantanamo would face further detention or prosecution in their own countries. The first of two new transfers is scheduled for the end of December, and the other in January, the official told The Associated Press on condition of anonymity.
The official did not say where the prisoners would be sent and a military spokeswoman declined Sunday to provide details about future transfers from the U.S. base at Guantanamo Bay, Cuba.
"We do expect there will be other transfers but because of operational procedures, I can't talk about any details," Lt. Col. Pamela Hart said. "We only talk about detainee movements after an operation is complete."
The military official who spoke on condition of anonymity said that one of the boys who would be transferred shot and killed a special operations soldier in Afghanistan, where a U.S.-led coalition ousted the Taliban regime in late 2001 and 11,500 American troops remain.
The official did not know why the boy was being released from U.S. custody, but the military has said previously that the main purpose of the detention mission is intelligence gathering.
On Sunday, a Canadian citizen returned home after being released in October from Guantanamo. Abdulrhaman Khadr was captured in Afghanistan and held as an "enemy combatant" by U.S. authorities for nine months, he told the Canadian Broadcasting Corp.
Khadr, the son of a suspected al Qaeda financier, said U.S. authorities refused to return him to Canada and instead flew him to Afghanistan.
After his release, Khadr went to Iran and then Turkey before arriving late last week in Bosnia, he told CBC.
At the Canadian Embassy in Sarajevo, Khader, who did not have a passport, was given a special permit to return to Canada, he told CBC. He was accompanied on his return to Toronto by a Canadian consular official.
The United States holds about 660 prisoners from 44 countries at the base in eastern Cuba but the government declines to provide a breakdown of their citizenship, ages or the reasons they are being held.
The government has not charged them or given them access to lawyers.
The United States has released 88 of the prisoners since the government began holding suspects at the base in Cuba in January 2002.
Maj. Gen. Geoffrey Miller, the official in charge of the detention mission, said Wednesday that the three youngest boys at the jail, who range from 13 to 15 would be transferred soon, but he did not give a date.
Before their capture by U.S. forces in Afghanistan, some of the youths held at the base were sexually abused; and they have received therapy at Guantanamo, the official said. The boys are kept separate from the adult population at the jail.
Separately, Britain and the United States are negotiating a deal to send nine British detainees back home.
Clive Stafford Smith, a U.S.-based British human rights lawyer, told The Observer, a British newspaper, that two of the nine British detainees, Asif Iqbal and Shafiq Rasul, were likely to be released and not charged with a crime while the other seven would serve sentences in British jails after pleading guilty to unspecified charges in the United States.
The British Foreign Office declined to confirm the report and said that discussions with U.S. officials were continuing.
CBS News foreign affairs analyst Pamela Falk called the news of the upcoming releases "a clear indication that the White House is under pressure from allies as well as from the Supreme Court to set standards for the holding of suspects in the war on terror."
Last month, the Supreme Court agreed to consider whether foreigners held at the U.S. Navy base in Cuba should have access to American courts. The appeals came from British, Australian and Kuwaiti citizens held there.
There has been criticism of Bush administration plans to try some of the Guantanamo detainees in military tribunals. The American Bar Association has pressed the administration to drop plans to let agents eavesdrop on conversations between terrorism suspects and defense lawyers and should ease other restrictions to ensure military tribunals are fair and open.
President Bush has recommended six detainees, including the Australian and two Britons, to be the first to face tribunals. It has not definitely been decided that they will be tried, nor on what charges.
Once the prosecutor decides on charges, Deputy Defense Secretary Paul Wolfowitz will then make a separate decision on whether the suspects will actually face trials by what the Pentagon calls military commissions.
The Pentagon has refused to state what the men were suspected of doing, where they were captured or where they might be tried. It also has not said what would happen if the men were found innocent, raising at least the possibility that they might still be detained even if acquitted.