Three senior members of the Islamic State of Iraq and al-Sham (ISIS) – including an aide to its leader – were killed in a U.S. airstrike in Iraq, a senior Iraqi security official told NBC News Thursday. The strike on the ISIS stronghold of Mosul killed Abu Hajar Al-Sufi, an aide to Abu Bakr al-Baghdadi, as well as an explosives operative and the military leader of the nearby town of Tel Afar, the source said on condition of anonymity. Al Arabiya cited the Iraqi Defense Ministry saying Baghdadi’s aide had been killed in the strike.