The strikes were the fourth on Beirut in less than a week. The escalation comes after a U.S. envoy traveled to the region this week in an attempt to broker a cease-fire between Israel and Hezbollah.

Israeli airstrikes on Saturday killed at least 11 people and injured dozens in central Beirut, as diplomats scrambled to broker a cease-fire. Lebanon’s civil defence said the death toll was provisional as emergency responders were still digging through the rubble looking for survivors.

A powerful Israeli air strike flattened a residential building in central Beirut early Saturday, killing at least 16 people and wounding 63 others, while a Hezbollah official denied it targeted a senior commander with the militant group.