The barrage came after an Israeli airstrike in Beirut on Friday killed at least 45 people, including one of Hezbollah's top leaders as well as women and children. Hezbollah was already reeling from a sophisticated attack that caused thousands of personal devices to explode just days earlier.

The Israeli military said that it carried out a wave of strikes across southern Lebanon over the past 24 hours, hitting about 400 militant sites, including rocket launchers. Lt. Col. Nadav Shoshani, an Israeli military spokesman, said those strikes had thwarted an even larger attack.

“Hundreds of thousands of civilians have come under fire across a lot of northern Isreal. They spent the night and now the morning in bomb shelters," he said. “Today we saw fire that was deeper into Israel than before.”

The military also said it had intercepted multiple aerial devices fired from the direction of Iraq, after Iran-backed militant groups there claimed to have launched a drone attack on Israel.

Israel's Health Ministry said that all hospitals in the north would begin moving operations to protected areas or shelters within the medical centers.

In a separate development, Israeli forces raided the West Bank bureau of Al-Jazeera, which it had banned earlier this year, accusing it of serving as a mouthpiece for militant groups, allegations denied by the pan-Arab broadcaster.

Israel and Hezbollah have traded fire since the outbreak of the war in Gaza nearly a year ago, when the militant group began firing rockets in solidarity with the Palestinians and its fellow Iran-backed ally Hamas. The low-level fighting has killed dozens of people in Israel, hundreds in Lebanon, and displaced tens of thousands on both sides of the frontier.

Until recently, neither side was believed to be seeking an all-out war, and Hezbollah has so far stopped short of targeting Tel Aviv or major civilian infrastructure. But in recent weeks, Israel has shifted its focus from Gaza to Lebanon and vowed to bring back calm to the border so that its citizens can return to their homes. Hezbollah has said that it would only halt its attacks if there is a cease-fire in Gaza, which appears increasingly elusive.

The war in Gaza began with Hamas' Oct. 7 attack into Israel, in which Palestinian militants killed about 1,200 people and took around 250 others hostage. They are still holding around 100 captives, a third of whom are believed to be dead. Over 41,000 Palestinians have been killed, according to Gaza's Health Ministry. It doesn't say how many were fighters, but says women and children make up more than half of the dead.

Families of the hostages have raised fears that a war in the north would distract from their plight and further complicate the negotiations over their release.

The U.N. envoy for Lebanon called on all parties to pull back.

“With the region on the brink of an imminent catastrophe, it cannot be overstated enough: there is NO military solution that will make either side safer,” Jeanine Hennis-Plasschaert said in an X post.

Israeli media reported that rockets fired from Lebanon early Sunday were intercepted in the areas of Haifa and Nazareth, which are further south than most of the rocket fire to date. Israel canceled school across the north, deepening the sense of crisis.

Hezbollah said that it had launched dozens of Fadi 1 and Fadi 2 missiles — a new type of weapon the group hadn't used before — at the Ramat David airbase, southeast of Haifa, “in response to the repeated Israeli attacks that targeted various Lebanese regions and led to the fall of many civilian martyrs.”

In July, the group released a video with what it said was footage it had filmed of the base with surveillance drones.

Hezbollah also said it had targeted the facilities of the Rafael defense firm, which is headquartered in Haifa, calling it retaliation for the wireless devices attack. It didn't provide evidence, and the Israeli military declined to comment on the statement.

Hezbollah has vowed to retaliate against Israel for a wave of explosions that hit pagers and walkie-talkies belonging to Hezbollah members on Tuesday and Wednesday, killing at least 37 people — including two children — and wounding around 3,000. The attacks were widely blamed on Israel, which hasn't confirmed or denied responsibility.

On Friday, an Israeli airstrike took down an eight-story building in a densely populated neighborhood in Beirut’s southern suburbs as Hezbollah members were meeting in the basement, according to Israel. Among those killed was Ibrahim Akil, a top Hezbollah official who commanded the group’s special forces unit, known as the Radwan Force.

Lebanese authorities say at least seven women and three children were killed in Friday’s airstrike and that dozens more were wounded. It was the deadliest strike on Beirut since the monthlong war in 2006 between Israel and Hezbollah.

Israeli Defense Minister Yoav Gallant said that the attack broke up the group’s chain of command while taking out Akil, who he said was responsible for Israeli deaths.

Akil had been on the U.S. most wanted list for years, with a $7 million reward, over his alleged role in the 1983 bombing of the U.S. Embassy in Beirut and the taking of American and German hostages in Lebanon during the civil war in the 1980s.