By Amber Henshaw
BBC News, Khartoum
Some 700,000 Sudanese children have grown up knowing nothing but war
There are as many as 6,000 child soldiers, some as young as 11 years old, in the war-torn region of Darfur, the head of Unicef in Sudan says.
Ted Chaiban said some children were linked to rebel movements, others to government-backed militia and some were fighting alongside the Sudanese army.
It is illegal under Sudanese and international law to have soldiers under the age of 18, he added.
The UN is trying to convince armed groups to release the children.
Mr Chaiban told journalists that some had signed up voluntarily but others had been forcibly recruited.
"Any child that has been in a conflict situation, that has witnessed and, more importantly, participated in violence basically becomes dehumanised," he said.
"They know something is wrong but they can not explain what is wrong... It separates them from their emotions and from their normal growth in a way that is much more severe than an adult going through the same experience."
It is hoped that hundreds of child soldiers will be demobilised next year.
The first group will be from the Sudan Liberation Army faction led by Minni Minnawi - one of the few rebel leaders to have signed a peace deal with the government.
Unicef has been negotiating with the other factions and hopes they will follow suit.
In total, Mr Chaiban said the child protection agency estimates that about 2.3 million children had been affected by the conflict in Darfur since it began almost six years ago.
Nearly 700,000 children, he said, had been born and grown up knowing nothing but war.