The detainees have been under heavy guard

The United States is to release about a dozen people held since the war in Afghanistan, defence officials have said.

Few details have been revealed about the prisoners, whose detention without charge at a US naval base in Guantanamo Bay, Cuba has drawn intense criticism from human rights organisations.

US Secretary of State Colin Powell complained in writing to the Pentagon last month about the detentions, which he said were undermining international support for the US war on terror.

Pentagon officials denied that the releases expected this week were connected to the complaint.

Twelve to 15 people, mostly Afghans are to be released.

The group may include at least some of the juveniles in the group. The US has come under particular criticism - including from the United Nations - for holding a small number of youths under the age of 16.

Taleban and al-Qaeda suspects

The US has refused to say exactly how many prisoners it holds, but there are believed to be about 660 from more than 40 different countries. Most are suspected of being members of the Taleban or al-Qaeda.

Mr Rumsfeld said four agencies were involved in questioning

US Defence Secretary Donald Rumsfeld said at the weekend he would like to expedite the processing of prisoners held at Guantanamo Bay.

But Mr Rumsfeld said it was necessary to question the detainees thoroughly.

"It takes time to find out what intelligence they have," he told CNN.

"It also takes time to figure out what law enforcement process might be appropriate.

"What [Mr Powell] and I have been concerned about... is that it's taking so long," he said.

The FBI, Department of Justice, CIA and the Pentagon's Defense Intelligence Agency were all involved in the process of interrogating the detainees, Mr Rumsfeld said.

Enemy combatants

Hundreds of people were taken prisoner by US-led forces in the war launched to overthrow the Taleban after the 11 September 2001 attacks on New York and Washington, blamed on al-Qaeda.

Few detainees have been released from Guantanamo Bay

The US started moving captives to its remote base in Cuba in January 2002. They have been classified as enemy combatants - not prisoners of war, who would have more rights.

None have been charged with a crime and few have been released.

The human rights group Amnesty International has long urged the United States to either charge the Guantanamo prisoners with crimes and try them or let them go.

Three children under the age of 16 are among the detainees, whose status means they have no rights to legal representation.