Nigeria's military says it is investigating reports that the leader of militant Islamist group <a href="https://www.thenationalnews.com/world/africa/nigerian-army-makes-fragile-gains-against-boko-haram-1.1153374">Boko Haram</a> may have been killed or seriously injured following clashes with a rival terror group. Abubakar Shekau has been the figurehead of an insurgency that has killed more than 30,000 people since 2009. In 2014, he made international headlines when his forces kidnapped about 300 schoolgirls. A number of reports published on Thursday by Nigerian media, citing intelligence sources, said Shekau was seriously hurt or killed after his insurgents clashed with members of Islamic State in West Africa Province (Iswap), which broke away from his group in 2016. A Nigerian Army spokesman, Mohammed Yerima, said the military were investigating. "It's a rumour. We are investigating it. We can only say something if we confirm it," he said. Shekau was said to have been killed on several occasions over the last 12 years, including in announcements by the military, only to later appear in a video. Iswap split from Shekau's group five years ago, pledging allegiance to ISIS. The schism was due to religious ideological disagreements over Boko Haram's killing of civilians – something Iswap objected to. Shekau's death, if confirmed, could potentially end fighting between the two groups, enabling either to absorb the others' fighters and consolidate its hold on north-east Nigerian. The ongoing conflict in Nigeria has forced about 2 million people from their homes and spawned one of the world's worst humanitarian crises.