BEIRUT — The leader of Lebanon’s Hezbollah said Thursday the mass bombing attack against it using its communications devices was a “severe blow” and said Israel had crossed a “red line.” But he said the group would continue its daily strikes into northern Israel, vowing Israelis would not be able to return to their homes there until the Gaza war ends.

As Hassan Nasrallah spoke in a televised speech from an unknown location, Hezbollah and the Israeli military traded new strikes over the border and at least two Israeli soldiers were killed. Israeli warplanes also flew low over Beirut and broke the sound barrier, scattering birds and prompting people in houses and offices to quickly open windows to prevent them from shattering.

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Fears of Escalation Rise After Unprecedented Bombings

Fears are rising that 11 months of exchanges of fire between the two sides will escalate into all-out war, particularly after this week’s unprecedented bombings widely blamed on Israel in which hundreds of pagers and walkie-talkies used by Hezbollah were remotely detonated in Beirut, parts of Lebanon and the Syrian capital Damascus.

At least 37 people were killed and some 3,000 wounded in the explosions, which appeared to be the culmination of a monthslong operation by Israel to target as many Hezbollah members as possible all at once, but which also hit civilians.

The attack came as Israeli leaders have warned that they could launch a stepped-up military operation against Hezbollah, saying they are determined to stop the group’s fire to allow tens of thousands of Israelis to return to homes near the border.

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Nasrallah Vows Retaliation, Continues Strikes on Northern Israel

Nasrallah said the group is investigating how the bombings were carried out.

“Yes, we were subjected to a huge and severe blow,” he said. “The enemy crossed all boundaries and red lines,” he said. Pointing to the number of pagers and walkie-talkies, he accused Israel of intending to kill thousands of people at one time. “The enemy will face a severe and fair punishment from where they expect and don’t expect.”

He said Hezbollah will continue its barrages into northern Israel as long as the war in Gaza continues, vowing that Israel will not be able to bring its people back to the border region. “The only way is stop the aggression on the people of Gaza and the West Bank,” he said. “either strikes, nor assassinations nor an all-out war will achieve that.”

While he spoke, Hezbollah announced at least four strikes into northern Israel, while Israeli strikes were reported in southern Lebanon. Earlier Thursday, Hezbollah said it had targeted three Israeli military positions near the border, two of them with drones. Israeli hospitals reported eight people lightly or moderately injured. Overnight, the miltiary said it struck several militant sites in southern Lebanon,

Hezbollah says its near daily fire is a show of support for Hamas. Israel’s 11-month-old war with Hamas in Gaza began after its militants led the Oct. 7 attack on Israel.

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Israel Warns of Potential Escalation in Northern Front

Israel has responded to Hezbollah’s fire with strikes in southern Lebanon, and has struck senior figures from the group in the capital Beirut. The exchanges have killed hundreds in Lebanon and dozens in Israel and forced the evacuation of tens of thousands of residents on each side of the border.

Israel and Hezbollah have repeatedly pulled back from an all-out war under heavy pressure from the United States, France and other countries.

But in their recent warnings, Israeli leaders have said they are determined to change the status quo dramatically.

Speaking to Israeli troops on Wednesday, Israeli Defense Minister Yoav Gallant said, “We are at the start of a new phase in the war — it requires courage, determination and perseverance.” He made no mention of the exploding devices but praised the work of Israel’s army and security agencies, saying “the results are very impressive.”

Gallant said that after months of fighting Hamas in Gaza, “the center of gravity is shifting to the north by diverting resources and forces.”

Israel began moving more troops to its border with Lebanon on Wednesday as a precautionary measure, Israeli officials said. Israel’s army chief, Lt. Gen. Herzi Halevi, said plans have been drawn up for additional action against Hezbollah, though media reported the government has not yet decided whether to launch a major offensive in Lebanon.

Lebanon is still reeling from the deadly device attacks of Tuesday and Wednesday.

The explosions have rattled anxious Lebanese fearing a full-scale war. The Lebanese Army said it has been locating and detonating suspicious pagers and communication devices, while the country’s civil aviation authorities banned pagers and walkie-talkies on all airplanes departing from Beirut’s international airport until further notice.

The attack was likely to severely disrupt Hezbollah’s internal communication as it scrambles to determine safe means to talk to each other. Hezbollah announced the death of five combatants Thursday, but didn’t specify if they were killed in the explosions or on the front lines.

The blasts went off wherever the holders of the pagers or walkie-talkies happened to be in multiple parts of Beirut and eastern and southern Lebanon — in homes and cars, grocery stores and cafes and on the street, even at a funeral for some killed in the bombings, often with family and other bystanders nearby.

Many suffered gaping wounds on their legs, abdomens and faces or were maimed in the hand. Tuesday’s pager blasts killed 12 people, including two children, and wounded some 2,300 others. The following day’s explosion killed 25 and wounded more than 600, Health Minister Firas Abiad said, giving updated figures.

Abiad told reporters that Wednesday’s injuries were more severe than the previous day as walkie-talkies that exploded were bigger than the pagers. He praised Lebanon’s hospitals, saying they had managed to deal with the flood of wounded within hours. “It was an indiscriminate attack. It was a war crime,” he said.