U.N. Secretary-General Ban Ki-moon called on the international community to back central African countries in their fight against the Lord's Resistance Army.
The LRA is suspected of using child soldiers in its militant campaign. Girls are used as sex slaves, the United Nations said, and the LRA has a reputation for killing and mutilating its victims.
Ban, in his report to the U.N. office in central Africa, said international backing was needed for a coordinated strategy to address the LRA threat.
"Only by providing the necessary resources will we be able to ensure the success of continuing efforts by the national authorities, the African Union and other international partners in this regard," he said in a statement.
LRA leader Joseph Kony remains at large despite a 2005 indictment by the International Criminal Court on more than 30 counts of violations of international law, including war crimes.
Radhika Coomaraswamy, U.N. special envoy for children and armed conflict, in a report this week, said the rebel group was casting a "long shadow" over the region.