ISWAP is an offshoot of the Boko Haram insurgent group that has been fighting against the Nigerian armed forces for over a decade.
The conflict, which has spilled into neighbouring Chad and Cameroon, has left about 300,000 dead and millions dependent on aid, the United Nations says.
Bako's death could not be independently verified, and there was no immediate confirmation from ISWAP.
Abuja,
Nigeria's army said on Thursday it had killed the new leader of insurgent group Islamic State West Africa Province (ISWAP) in a military operation this month, two weeks after announcing the death of the group's former head Abu Musab al-Barnawi.
ISWAP is an offshoot of the Boko Haram insurgent group that has been fighting against the Nigerian armed forces for over a decade. The two militant groups later turned on each other.
The conflict, which has spilled into neighbouring Chad and Cameroon, has left about 300,000 dead and millions dependent on aid, the United Nations says.
Army spokesman Brigadier Benard Onyuko said in a statement that Nigerian troops had conducted several land and air raids on suspected insurgent locations, during which ISWAP's new leader, Malam Bako, was killed.
"In the course of the operations within the period, a total of 38 terrorist elements were neutralized, including the ISWAP's new leader, Bako," Onyuko said without elaborating.
Bako's death could not be independently verified, and there was no immediate confirmation from ISWAP.
If confirmed, Bako would be the fourth leader of an Islamist insurgent group in West Africa to die this year, after Boko Haram leader Abubakar Shekau in May, Adnan Abu Walid al-Sahrawi of Islamic State in the Greater Sahara (ISGS) in August and al-Barnawi this month.
Since Shekau's death, thousands of Boko Haram fighters have surrendered to the Nigerian armed forces.