The strikes, which destroyed an eight-story building and left a crater in the ground, were the fourth in Beirut in less than a week.

The envoy, Amos Hochstein, was in Israel and planned to meet with Prime Minister Benjamin Netanyahu, seeking a truce in the country’s war with the militant group Hezbollah.

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.

The escalation comes after a U.S. envoy traveled to the region to pursue a deal to end months of fighting between Israel and Hezbollah.

US envoy Amos Hochstein arrived in Beirut in a bid to secure a cease-fire deal between Israel and Hezbollah, as the Lebanese group reportedly approved a new proposal to halt the hostilities, with some comments.

Saturday’s attack completely demolished a multistory building in a densely populated neighborhood. Israel did not say who the strike’s target was.

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.