Israel carried out one of the most intense bombardments of the past year, as warplanes launched 70 airstrikes, Lebanese security officials said. The barrage came shortly after Hezbollah’s leader vowed to respond after explosions of pagers and walkie-talkies killed at least 37 people.

Lebanon’s death toll from a series of walkie-talkie and pager explosions this week rose to 37, according to local authorities, an illustration of the devastation wrought by a wave of suspected Israeli attacks aimed at Hezbollah militants.

Thousands of pagers and walkie-talkies used by the Hezbollah militant group exploded earlier this week, killing dozens and injuring thousands of others.

The Israeli army said it struck hundreds of targets in Lebanon on Thursday as fears of full-scale war soared. Early voting in the U.S. presidential election begins in the U.S. state of Minnesota on Friday.