The new chief spokesman for the Islamic State group (also called ISIS) promised attacks on the United States, Russia, Europe and Iran in his first address to the terrorist outfit’s followers, which was released Monday by ISIS’s al-Furqan media division The audio recording named Abu Hassan al-Muhajir as the successor to Abu Muhammad al-Adnani, who was killed in a U.S. drone strike near al-Bab, Syria, on Aug. 30. In a chilling message — titled “For You Will Remember What I Tell You” — aimed at the West and ISIS's regional adversaries, Muhajir called on the group's fighters to target its...