The UN says more children are being recruited into armed conflict in West and Central Africa than anywhere else in the world.
The UN children's agency, Unicef, found more than 20,000 children had joined armed groups over the last five years.
It says children are used as fighters as well as messengers, spies, cooks, cleaners, guards and porters in countries from Mali to the Democratic Republic of Congo.
West and Central Africa also had the highest number of child victims of sexual violence in the world and the second highest number of abductions.
The region has several ongoing armed conflicts including Islamist insurgencies and separatist wars.
Unicef is calling for increased support for efforts to prevent and respond to grave violations against children.