A report on the situation in Mali from U.N. Secretary-General Ban Ki-moon said destabilization since a 2012 coup was characterized by grave violations against women and children.
His report to the U.N. Security Council said children were "severely affected" by conflict in northern Mali.
Leila Zerrougui, U.N. special envoy for children and armed conflict, said sexual violence was "widespread and systematic in northern Mali."
Nomadic rebels and al-Qaida fighters took control over northern Mali after the coup.
Zerrougui said there are reports of boys as young as 12 enlisted as patrolmen by rebel forces that took control of northern Mali following the coup.
"I am working to make sure that the deployment of a peacekeeping mission, in conjunction with the work of U.N. agencies and partners already on the ground, will allow us to improve our collective response to children's needs," she said in a statement published Wednesday.
The U.S. State Department expressed concern last week about the security situation in northern Mali. Pro-government and rebel forces were suspected of human rights abuses as they battled in Kidal, one of the last northern regions controlled by the rebels.