The Israeli military carried out dozens of airstrikes against the Lebanese militant group Hezbollah on Thursday, one of the most intense waves of bombardment this year. The strikes came hours after Hezbollah’s leader vowed that “retribution will come” to Israel after audacious attacks on Hezbollah’s pagers and walkie-talkies.

The device explosions killed at least 37 people and left many Israelis and Lebanese fearful of a worsening conflict between Hezbollah and Israel.

In his first speech since the devices blew up Tuesday and Wednesday, Hezbollah leader Hassan Nasrallah conceded that his group had “endured a severe and cruel blow.” He accused Israel of breaking “all conventions and laws” and said that it would “face just retribution and a bitter reckoning.”

But he did not describe how Hezbollah, which Iran backs, might retaliate, saying, “I will not discuss time, nor manner, nor place.”

Israel has not confirmed or denied responsibility for the device explosions, although current and former defense and intelligence officials who were briefed on the attacks say Israel was behind them.

Shift in focus

In recent days, Israeli officials have signaled that their focus has been shifting from the war against Hamas in the Gaza Strip to the fight against Hezbollah in Lebanon. The Israeli military has increasingly devoted resources and personnel to that conflict, which has taken place mostly along its northern border. Israel’s defense minister, Yoav Gallant, said Israel was embarking on “the new phase of the war.”

The Israeli military said in a statement that Thursday’s airstrikes targeted approximately 100 rocket launchers belonging to Hezbollah, along with other sites. Three senior Lebanese security officials, who spoke on the condition of anonymity because they were not authorized to speak to the news media, said Israel carried out more than 70 airstrikes Thursday.

The Israeli bombardment was a marked uptick from the daily tit-for-tat attacks that have characterized the cross-border fighting for the past 11 months. But it did not appear to be a major step toward full-blown war: There were no immediate reports of casualties, and the strikes seemed to have avoided major population centers and the Lebanese heartland.

Israeli fighter jets also ripped through the skies above Beirut during Nasrallah’s speech, flying at low altitude in a show of military might. Two deafening sonic booms from the jets shook buildings and sent residents running into the street.

Hezbollah response

Nasrallah said the exploding devices would not deter Hezbollah from launching more rockets and drones at Israel in support of Hamas’ fight in Gaza. In a statement, Hezbollah said it had already executed 17 separate attacks on northern Israel on Thursday, targeting what it said were military bases and barracks. The Israeli military said two soldiers had been killed in combat in northern Israel but did not provide details.

Nasrallah’s speech, which he gave from an undisclosed location, appeared on televisions in apartment windows, cafes and shops across Lebanon as residents tensely watched to hear what he would say. Nasrallah said Hezbollah had received messages suggesting that Israel had booby-trapped the devices to try to force his fighters to stop their military operations.

“We will call them the Tuesday and Wednesday massacres,” Nasrallah said of the blasts. “Genocide? A great aggression against Lebanon, its people, its resistance, its sovereignty and security? War crimes, or a declaration of war? You can call it anything, and deservedly so.”

The attacks made many Lebanese citizens fear that other devices could explode. Some hurried to disconnect appliances. Others unplugged the inverters and solar systems powering their homes. Many kept cellphones away from their bodies and refused to answer calls. Baby monitors, televisions, laptops — residents viewed them all with suspicion. On Thursday, Lebanon’s aviation authority banned pagers and walkie-talkies from all flights leaving Beirut.

Gallant said Thursday that Hezbollah would “pay an increasing price” going forward. He reiterated that Israel’s war with the group had entered “a new phase” that carried “opportunities as well as significant risks.”