NEW : Prime Minister Mikati declares a day of mourning , but one man of action is needed . The blast in an East Beirut commercial district leaves mangled cars and charred buildings . The slain government official led a trial of a man accused of hiring would - be assassins . There are fears the attack could spur more violence between Shiite and Sunni Muslims .
NEW : Prime Minister Mikati declares a day of mourning , but one man says action is needed . The blast in an East Beirut commercial district leaves mangled cars and charred buildings . The slain security official led a probe of a man accused of arming would-be assassins . There are fears the attack could spur more violence between Shiite and Sunni Muslims .