A news agency linked to the self-styled Islamic State terrorist group, Amaq, has claimed that Abu Omar al-Shishani, reported to be the group’s chief military strategist, has been killed south of Mosul. Previous media reports of his death later proved to be unfounded. Al-Shishani, better known as Omar the Chechen, reportedly “died in combat” near the Iraqi city of Shirqat, 100 km from the IS stronghold of Mosul, RT reported. Iraqi government forces say they have almost encircled Shirqat, as they drive their offensive northward into the heart of IS territory. The Pentagon is verifying whether al-Shishani died in a US drone strike carried out earlier this month, officials told CNN. Washington previously boasted that it took out al-Shishani, who has a $5 million bounty on his head, in Syria in March, only to backtrack when IS said he survived his injuries.