Israel launched a wave of airstrikes against Hezbollah targets in Lebanon Thursday, as the militant group’s leader said two days of debilitating attacks on its members amounted to a declaration of war.

The strikes came hours after Hezbollah’s leader vowed that “retribution will come” to Israel for the explosions of Hezbollah members’ hand-held devices. At least 37 people were killed and more than 2,900 others injured in those explosions on Tuesday and yesterday. Here’s the latest.