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.

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.