What will Iran's response be to Israel's assassination of Hezbollah chief Hassan Nasrallah? Lebanon’s Hezbollah group confirmed on Saturday that its leader and one of its founding members, Hassan Nasrallah, was killed in an Israeli airstrike in a southern suburb of Beirut. An Iranian official said on Sunday that militant groups would carry on confronting Israel with Tehran's help. What exactly can be their response? FRANCE 24's William Hilderbrandt asked Kawa Hassan, non-resident fellow in the MENA Program à the Stimson Center, in Brussels, Belgium.