Nigeria’s top general said on Thursday that Abu Musab al-Barnawi, leader of the insurgent group Islamic State West Africa Province (ISWAP), was dead. ISWAP is an offshoot of the Boko Haram insurgent group that has been fighting against the Nigerian armed forces for 12 years. The two militant groups later turned on each other. The conflict between the insurgents and Nigeria’s armed forces, which has also spread to neighbouring Chad and Cameroon, has left about 300,000 dead and millions dependent on aid. “I can authoritatively confirm to you that Abu Musab is dead,” Lucky Irabor, the chief of defence staff, told reporters at the presidential villa in Abuja, without elaborating. Al-Barnawi was originally part of Boko Haram, led by Abubakar Shekau, who pledged allegiance to Islamic State in 2015. But the following year Islamic State named al-Barnawi as its leader in West Africa. Shekau rejected his demotion and the two groups split, with al-Barnawi moving his ISWAP fighters to the shores of Lake Chad, where they became the dominant insurgency. In June this year, al-Barnawi announced in an audio recording that his rival Shekau had died after detonating an explosive device while being pursued by ISWAP fighters following a battle. Since Shekau’s death, the Nigerian armed forces say that thousands of Boko Haram fighters have surrendered to them. In previous years, the Nigerian authorities erroneously announced Shekau’s death several times. The Daily Trust, a northern Nigerian newspaper, reported that al-Barnawi had died in late August, citing unnamed sources. It said different sources had given different accounts of how the ISWAP leader had died.