Hezbollah pounded northern Israel with 140 rockets Friday, a day after the militant group’s leader vowed to retaliate against Israel for a mass bombing attack, the Israeli military and the militant group said.

Israel has claimed the death of a senior Hezbollah military official after a rare Israeli airstrike in Beirut killed at least 37 people and wounded dozens more, shortly after Hezbollah pounded northern Israel with 140 rockets.

Hundreds of thousands of people sought shelter from Hezbollah rockets fired from Lebanon into northern Israel on Sunday, the military said, as a UN official warned of imminent regional "catastrophe" from the worsening violence.