Three Afghan boys freed last week from US custody in Cuba are back home with their families.
The boys were reportedly kept apart from other adult prisoners
The boys - thought to be aged between 13 and 15 - were the youngest detainees at the controversial Guantanamo base.
They were suspected of fighting with the Taleban against US-led forces which invaded Afghanistan in 2001.
The boys' detention without trial was attacked by human rights groups - one of them is thought to have been only 11 when arrested.
The BBC's Andrew North in Kabul says the Red Cross, which helped re-unite the boys with their families, has been keen to avoid drawing publicity to their return.
The boys are still minors and there are fears of reprisals against them.
"They were in good form," General Baba Jan, Kabul's police chief, told Reuters. "They said they were kept in a separate cell from the elderly inmates and were allowed to play and have fun."
An official said the Red Cross wanted the boys' return to be completed before the current Islamic holiday of Eid al-Adha began.
Our correspondent says the policy seems to have worked because many people in Kabul are still not aware the boys are back home.
Age is not a determining factor in detention - we detain enemy combatants who engaged in armed conflict against our forces or provided support to those fighting against us
Two of the families travelled to Kabul from the south-east last Thursday and took the boys straight home by bus that day.
The third boy was flown to the southern city of Kandahar in a Red Cross plane, where he was quickly handed over to his waiting family.
It is believed he has gone home to the south-western province of Helmand.
More than 600 suspected al-Qaeda and Taleban fighters have been held without charge at the base since the US-led war in Afghanistan, which followed the 11 September attacks in 2001.
Eighty seven detainees have now been released from the prison.
Two of the boys were captured during raids on Taleban camps in Afghanistan; the other was captured allegedly trying to obtain weapons for the Taleban.
In August, the US general running Guantanamo agreed they should be released, but said he was awaiting orders from senior defence officials.
The Pentagon said the boys' names were not being released for fear of reprisals against them.