The sabotage operation was an “unprecedented” attack by Israel, Hassan Nasrallah has said Israel committed a “massacre” by detonating thousands of pagers across Lebanon, Hezbollah leader Hassan Nasrallah has said, describing the operation, widely attributed to Israel’s Mossad, as “a declaration of war.”

In a highly anticipated speech following this week’s attacks, Nasrallah accused Israel of committing a “massacre” without regard for civilian casualties.

”This is sheer terrorism. We’ll call them Tuesday’s massacre and Wednesday’s massacre. These are war crimes or at least a declaration of war,” Nasrallah said. Noting that some of the devices had detonated in schools, hospitals, and residential buildings, the Hezbollah chief said the operation had crossed “all restrictions and red lines.” “There is no doubt that we suffered a major security and humanitarian blow, unprecedented in the history of our resistance,” he conceded. “We have been hit hard, but this is the state of war, and we understand that the enemy has technological superiority.”

Thousands of pagers – a low-tech and supposedly secure method of communication used by Hezbollah members – simultaneously detonated across Lebanon on Tuesday, killing a dozen people and injuring 3,000 more. A second wave of explosions took place on Wednesday, this time affecting handheld radios. As of Thursday, a total of 37 people had been killed, including at least two children, according to Lebanon’s health ministry.

While Israel has not claimed responsibility for the blasts, American, Israeli, and Lebanese sources have identified Israel’s Mossad intelligence agency as the culprit. Citing anonymous sources, the New York Times claimed on Thursday that Mossad had set up a fake company in Hungary to produce the devices under license from a Taiwanese firm. The pagers were stuffed with an explosive compound called PETN, which could be remotely triggered, and were shipped to Lebanon from 2022, the newspaper claimed. American officials told Axios on Wednesday that Mossad had intended to trigger the pagers as the first blow in an all-out war with Hezbollah, but decided to detonate them early in case Hezbollah discovered the plot.

Immediately after Wednesday’s explosions, Israeli Defense Minister Yoav Gallant announced that “a new phase” of Israel’s almost year-long war was beginning, this one focused on Hezbollah rather than Hamas. “The center of gravity is moving north. We are diverting forces, resources, and energy toward the north,” he said, according to a statement published on social media by his office.