Israel bombed the center of Beirut for the first time in almost a year of hostilities with Lebanon’s Hezbollah, as the military steps up air assaults following the killing of the Iran-backed group’s chief last week.

The Islamist Hezbollah militia in Lebanon vowed on Monday to quickly choose a successor to killed leader Hassan Nasrallah, and said it would continue its decades-long fight against Israel, even as it faced a massive escalation in military pressure.