At least 20 people were killed in a powerful Israeli strike that flattened a multi-storey building in densely populated central Beirut, Lebanese officials said on Saturday, as more deaths were reported from Israeli attacks in eastern Lebanon.

Israeli airstrikes Saturday in central Beirut killed at least 20 people, officials said, as the once-rare attacks on the heart of Lebanon's capital continued without warning while diplomats scrambled to broker a cease-fire.

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.