The U.N. says a 4-year-old girl and an Ethiopian peacekeeper were killed and three others wounded in an attack on Thursday in the contested Abyei area between Sudan and South Sudan.

The U.N. Interim Security Force for Abyei, or UNISFA, said in a Friday statement that an unknown group of "anti-peace elements" fired rockets and small arms onto the town of Abyei, which sits along the presumed border between the South Sudan-aligned Ngok Dinka tribe in the south of Abyei and the Sudan-aligned Arab Misseriya in the north.

UNISFA said most of the shells landed in and around the home of the Ngok Dinka chief and that peacekeepers have been sent in to secure the area.

Ownership of oil-rich Abyei remains disputed following South Sudan's split from Sudan in 2011.