By Celeste Hicks
BBC News, N'Djamena
The UN is working to release more than 80 child soldiers taken prisoner by the Chad army during fighting with rebels.
The children were seized from the rebel Union of Resistance Forces (UFR) group, the UN children's fund (Unicef) says.
The UFR mounted a failed attack in the east of Chad early in May which led to troops capturing many prisoners.
On Wednesday, Unicef staff finally began interviewing the children to establish their age and identity. Some are believed to be as young as 13.
It is hoped they will all be released to a demobilisation centre in N'Djamena as soon as possible.
The issue has been highlighted by the British actor Ralph Fiennes, who has just concluded a visit to Chad as a Unicef goodwill ambassador.
More than 200 prisoners were taken at the battle of Am Dam in May, where the UFR rebels suffered a big defeat which forced them to retreat completely.
Bodies of young soldiers were seen scattered on the battlefield, and pictures of the young captives were shown on national television.
Unicef and the International Committee of the Red Cross have been pushing the Chadian government to grant them access to the children since they were transferred from the east to a jail in N'Djamena.
On a visit to Goz Beida in the east of Chad, the home region of many of these children, actor Ralph Fiennes met the mother of a 17-year-old boy who disappeared to join the rebels in 2006.
He took a photograph of the family and was able to show it to the missing son who he found in the demobilisation centre in N'Djamena.
"Someone has had to witness their child being taken and possibly brutalised and the huge distress that must be to a mother," Mr Fiennes said.
Chad says it inflicted a significant blow to the rebels at Am Dam
"This woman that we talked to had an extraordinary dignity and pride, and to speak your story to someone, the actual speaking of it can sometimes be helpful to people," the actor added.
In 2007 Chad signed the Paris Engagements on the protection of children which obliges them to prevent the recruitment of child soldiers.
While Unicef says the government has been helpful in granting access to the most recent captives, the use of children by all sides in the conflict in eastern Chad and across the border in Sudan's Darfur region continues unabated.
Chad's government accuses Sudan of sending armed rebels over the border from Darfur, a claim Khartoum rejects.