India, May 19 -- The Nigerian military said Monday that a new operation with US forces has killed more than 20 Islamic State group militants in northeastern Borno State.

The operation in Metele followed the weekend killing of Abu Bakr al-Mainuki, deputy leader of the group's local West African "province," marking a new development in the military cooperation. It was the first successful targeting of a senior militant leader by Nigeria's security forces after well over a decade of insurgency by armed groups, including Boko Haram.

The US military said no US or Nigerian forces were harmed in Sunday's strikes in the community near the borders with both Niger and Chad. Nigerian military spokesperson Samaila Uba said efforts "in close coordin...