Hezbollah launched rockets at Israel from Lebanon early Monday, prompting Israel to retaliate with a wave of airstrikes in an escalation that threatened to further destabilize the region as both the United States and Israel ramped up their ᴀssault in Iran.

The Israeli military soon responded to the attacks from Hezbollah, an Iran-backed militant group. The group took responsibility for the attacks and said it was acting to avenge the death of Ayatollah Ali Khamenei. Iran’s supreme leader was killed on Saturday in a joint U.S.-Israeli military operation, dying in an Israeli missile strike based on U.S. intelligence.

At least 31 people have been killed so far in Israeli airstrikes in Lebanon, the Lebanese Health Ministry said in a statement carried by the government’s official media.

In the second day of intense airstrikes and bombing runs on Iran, the United States and Israel hit more than 2,000 targets, while Iran launched hundreds of missiles and drones against Israel and Persian Gulf countries.