BEIRUT, LEBANON -- Israel and Hezbollah exchanged fire on Saturday as rescue crews in Beirut searched the rubble of an apartment building that was leveled by an Israeli airstrike that killed at least 37 people, including one of the militant group's senior leaders as well as women and children.

The Israeli government braced for an expected surge in Hezbollah rocket attacks by setting new caps on the size of gatherings and other restrictions in the north of the country, near Israel's border with Lebanon, that led to schools in some communities canceling classes on Sunday.

The airstrike Friday took down an eight-story building in a densely populated neighborhood in southern Beirut 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鈥檚 special forces unit the Radwan Force. Also killed was Ahmed Wahbi, a top commander in the group鈥檚 military wing, the Israeli military said.

Israel's defense minister, Yoav Gallant, said the attack, which came days after devastating coordinated attacks on Hezbollah that used exploding pagers and walkie-talkies, thwarted the group's chain of command while taking out Akil, who he said was responsible for Israeli deaths and who was on the U.S. wanted list for years.

鈥淭his is our commitment to the fallen and their loved ones. This is our commitment to the residents of the north. And this is a clear message to all those who seek to harm us,鈥 he posted on X.

Lebanon鈥檚 health minister, Firass Abiad, told reporters that at least seven women and three children were killed in Friday's airstrike on the building. He said another 68 people were injured, including 15 who were hospitalized.

It was the deadliest strike on Beirut since the 2006 Israel-Hezbollah war, and the casualty count could grow, with 23 people still missing, a government official said.

Hezbollah confirms more than a dozen operatives were killed

Akil, the main target, had been wanted by the U.S. for years for his alleged role in the 1983 bombing of the U.S. Embassy in Beirut and the taking of American and German hostages in Lebanon in the 1980s. The U.S. State Department last year announced a reward of up to $7 million for information leading to his 鈥渋dentification, location, arrest, and/or conviction.鈥

White House national security adviser Jake Sullivan called Akil鈥檚 death 鈥渁 good outcome鈥 and said he had 鈥淎merican blood on his hands鈥 for the embassy attack.

鈥淵ou know, 1983 seems like a long time ago,鈥 Sullivan said. 鈥淏ut for a lot of families and a lot of people, they鈥檙e still living with it every day.鈥

Wahbi was described as a commander who played major roles within Hezbollah for decades and was imprisoned in an Israeli jail in southern Lebanon in 1984. Hezbollah said he was one of the 鈥渇ield commanders鈥 during a 1997 ambush in southern Lebanon that left 12 Israeli troops dead.

Hezbollah announced overnight that 15 of its operatives had been killed by Israeli forces, but it didn鈥檛 how or where they died. Meanwhile, the Israeli army spokesperson, Lt. Col. Nadav Shoshani, said Saturday 16 Hezbollah fighters were killed in Friday鈥檚 strike.

Israel airstrikes and Hezbollah rocket attacks continue

It wasn鈥檛 immediately clear if anyone was killed or wounded in the back-and-forth attacks between Israel and Hezbollah on Saturday. The Israeli military confirmed that about 90 rockets had been fired at northern Israel and that Israel had struck more than 400 rocket launchers in Lebanon during the day.

Expecting a surge in rocket attacks, Rear Adm. Daniel Hagari, an Israeli defense spokesman, announced updated safety guidelines for areas north of Haifa, including caps on gatherings of 30 people in open spaces and 300 in enclosed spaces. Work and school can continue if people can reach protected areas in a timely manner. But since students and teachers in some places wouldn鈥檛 be able reach shelters in the required time, Sunday classes were canceled in at least two border regions within an hour of the announcement.

Earlier this week, Israel鈥檚 security cabinet said stopping Hezbollah鈥檚 attacks on the country鈥檚 north, which would allow displaced residents to return to their homes, is now an official war goal, as Israel considers a wider military operation in Lebanon that could spark an all-out conflict. Israel has since sent a powerful fighting force to its northern border.

Hezbollah has maintained that it will halt its strikes only when a cease-fire is reached between Israel and Hamas in Gaza,

Israel and Hezbollah have traded fire regularly since Hamas鈥 Oct. 7 assault on southern Israel ignited the Israeli military鈥檚 devastating offensive in Gaza. But previous cross-border attacks have largely struck areas in northern Israel that had been evacuated and less-populated parts of southern Lebanon.

Hezbollah bombardments preceded the Israeli strike

Friday's strike came hours after Hezbollah launched one of its most intense bombardments of northern Israel in nearly a year of fighting, largely targeting Israeli military sites. Israel鈥檚 Iron Dome missile defense system intercepted most of the Katyusha rockets.

The militant group said its latest wave of rocket salvos was a response to Israeli strikes on southern Lebanon. However, it came days after mass explosions of Hezbollah pagers and walkie-talkies killed at least 37 people, including two children, and wounded roughly 3,000 others.

Abiad, the Lebanese health minister, said Saturday that hospitals across the country were filled with the wounded.

The pager and walkie-talkie attacks have been widely attributed to Israel, which hasn't confirmed or denied involvement. They marked a major escalation in the past 11 months of simmering conflict along the Israel-Lebanon border.

Associated Press writers Jack Jeffery and Natalie Melzer in Jerusalem, White House correspondent Zeke Miller in Wilmington, Delaware, and Amir Vahdat in Tehran, Iran, contributed to this report.