It is not clear who would replace al-Baghdadi if he was killed — the group has lost many of its senior commanders, killed in U.S.-led airstrikes, including Fadhil Ahmad al-Hayali, said by U.S. officials to be the No. 2 leader of the group. Al-Hayali was killed in an August 2015 airstrike by the U.S. in Iraq. Two other top figures, IS spokesman Abu Mohammed al-Adnani, and Abu Ali al-Anbari, the extremist group's leading finance official, were killed in 2016.