An Israeli airstrike killed at least 20 people in central Beirut on Saturday, Lebanon's health ministry said, one of the deadliest strikes on the heart of the capital since Israel began its assault against the Iran-backed Hezbollah group in September.

Israel was targeting a senior Hezbollah commander, but failed to kill him, one Israeli official said. Hezbollah officials said none of the group’s leaders were at the attack site.

BEIRUT — A massive Israeli airstrike that hit a residential building in a central district of Beirut early Saturday killed at least 20 people, thundered across the city and underlined fears in Lebanon that the war is escalating, days after diplomatic ...