A report to the U.N. Security Council states that close to 600 children, including more than 250 girls, were abducted and conscripted into the LRA from Democratic Republic of Congo, the Central African Republic and South Sudan in during a 3-year period beginning in 2009.
Radhika Coomaraswamy, U.N. special envoy for children and armed conflict, said the LRA was committed grave human rights violations against children in the region.
"The LRA continues to cast a long shadow across central Africa, causing enormous suffering for children," she 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.
U.N. officials had warned that renewed pressure on the LRA could prompt the militant organization to go on the offensive. Formed in the 1980s, the group is believed to consist of 200-500 fighters.