IS spokesman and head of external operations Abu Muhammad al-Adnani is pictured in this undated handout photo, courtesy the U.S. Department of State. The United States carried out an air strike in Syria's town of al-Bab targeting a senior Islamic State official, a U.S. defense official told Reuters on August 30, 2016. U.S. Department of State/REUTERS ATTENTION EDITORS - THIS IMAGE WAS PROVIDED BY A THIRD PARTY. EDITORIAL USE ONLY - RTX2NNYQ