Qassem, whose promotion from deputy leader was announced on Tuesday, replaces Hassan Nasrallah as secretary-general of the Lebanon-based armed group.Nasrallah was killed in Beirut in late September by an Israeli strike. Many other senior Hezbollah officials have also been targeted since Israel turned its focus on the group that month.Nasrallah was killed in Beirut in late September by an Israeli strike. Many other senior Hezbollah officials have also been targeted since Israel turned its focus on the group that month.