Israel brought its fight with Hezbollah to the doorstep of Beirut, with a series of overnight attacks on the city’s southern suburbs following a massive airstrike aimed at killing the group’s leader Hassan Nasrallah.
Israeli officials were still assessing whether Nasrallah had been killed in the strike but felt it was unlikely he had survived, people familiar with the matter said. Other leaders of the militant group and members of Iran’s Islamic Revolutionary Guard Corps also were present at the site, other people familiar with the matter said.
Smoke hung over much of the city’s south as dawn broke Saturday, with narrow columns rising up from the impact sites as residents got their first look at the results of the bombardment.
Images broadcast live by local media showed scenes of destruction in the area’s residential and commercial streets, with burned-out cars, debris strewn across roads and fires still raging.
Other areas of the city were unusually full with residents of southern neighborhoods who fled their homes overnight after Israel warned them to evacuate ahead of the wave of bombings that followed the strike at Nasrallah.
That attack flattened part of a neighborhood in an attempt to kill the cleric who has led the group for three decades and built it into a fearsome foe. Israel’s military said Hezbollah’s main headquarters was hidden under the buildings.
Later, close to midnight local time, Israel’s military warned residents of some neighborhoods in Beirut’s southern suburbs to leave immediately, saying it planned to carry out new operations against three buildings with what it called strategic capabilities for Hezbollah underground. Some residents reported getting an automated call from Israel with a warning to evacuate.
The strikes began 90 minutes later. Israel’s military said it hit Beirut in three waves overnight and into early Saturday morning. Shortly after midnight, the military said it targeted antiship missiles it said were stored under three residential buildings. Less than three hours later, the military said it struck weapons production and storage facilities, as well as what it said were key Hezbollah command centers.
Ali al-Harakah, a municipal official in Haret Hreik district, said civil-defense teams conducting rescue operations were exhausted after responding to the strikes overnight, but he expected them to return to work as day broke in the city.
Lebanon’s Ministry of Health called on hospitals in nearby areas to stop taking in nonemergency cases to make room for patients being evacuated from hospitals in the southern suburbs.
The series of attacks targeting Nasrallah and southern Beirut were Israel’s most aggressive moves yet in two weeks of elaborate intelligence operations, targeted killings and heavy bombardments aimed at stopping Hezbollah from attacking across the Lebanese border into Israel.
Nasrallah’s death would be an enormous blow not only to the group he leads, but also to its main backer, Iran, and the wider network of aligned militias that Tehran has built across the Middle East to confront Israel. It also would be the strongest signal yet that Hezbollah has been thoroughly penetrated by Israeli intelligence.
Israel hoped his death could significantly degrade the group and head off the need for a ground invasion to silence Hezbollah’s rocket, missile and drone attacks across the border.
“His powerful leadership is different,” a senior Israeli official said. “Some people are irreplaceable.”
Nasrallah oversaw Hezbollah’s transformation into the world’s most heavily armed nonstate militia and its integration into Lebanon’s political system.
He has found himself increasingly isolated in recent weeks by Israel’s relentless campaign of targeted killings of his most trusted fighters. Israel killed top lieutenant Fuad Shukr, who had eluded the U.S. for four decades, in an airstrike this summer on his apartment on the upper floors of a southern Beirut residential building, where he had been summoned by a phone call shortly before.
Thousands of Hezbollah pagers and walkie-talkies exploded virtually simultaneously last week, killing 37 people and injuring around 3,000. Shortly afterward, an airstrike in Beirut killed a group of more than a dozen elite military leaders. Strikes in southern Beirut this week killed Hezbollah’s top missile commander and another commander in the group’s aerial unit.
The moves have been part of a campaign by Israel to degrade Hezbollah’s strength and push it back from the border without having to resort to a military incursion.
“Our preference is to not have a ground invasion,” the senior Israeli official said. “This could be a pivot.”
Hezbollah began firing across the border shortly after the Hamas-led Oct. 7 attacks on southern Israel that killed 1,200 people and sparked the war in Gaza. The two foes have traded fire almost daily since then, depopulating strips along both sides of the border and raising concerns of escalation into a wide war.
On Saturday morning, a surface-to-surface missile fired from Lebanon landed in central Israel, the sound of its explosion rippling through Tel Aviv and surrounding cities. The Israeli military said it let the missile fall in an open area, in line with interception protocols.
Israel stepped up its attacks over the summer and sharply escalated them over the past two weeks, as pressure built on the government to return residents evacuated from the north to their homes.
The strike at Nasrallah at around 6:20 p.m. local time came shortly after Israeli Prime Minister Benjamin Netanyahu addressed the United Nations General Assembly in New York. “We will not accept a terror army perched on our northern border able to perpetrate another Oct. 7-style massacre,” Netanyahu said.
Netanyahu’s speech came before a largely empty U.N. chamber, after dozens of diplomats walked out when it was announced that Netanyahu was next to speak. His comment came amid U.S.-led efforts to seek a diplomatic solution before all-out war breaks out.
U.S. Defense Secretary Lloyd Austin warned of the consequences if a cease-fire deal wasn’t reached.
“An all-out war between Lebanese Hezbollah and Israel would be devastating for both Lebanon and Israel,” Austin told CNN’s Wolf Blitzer on Friday. “And again, we anticipate that we’d see a number of people displaced, casualties that, you know, equal or exceed what we’ve seen in Gaza.”
Austin spoke with his Israeli counterpart late Friday, during what a U.S. official described as a tense phone call, in part because Israel didn’t give the U.S. advance notice of the strike. For the U.S., any tension could spill over to American forces in the region.
Israeli strikes have killed more than 600 people in Lebanon since Monday, including scores of women and children, and injured around 2,000, according to the Lebanese Ministry of Health.
More than 200,000 people have been displaced in Lebanon as a result of the conflict with Israel since October, with about 100,000 newly displaced people in the past week, some moving for a second time, according to a report from the International Organization for Migration.
Israeli jets also struck targets in the Beqaa region, the coastal city of Tyre and southern Lebanon overnight. Hezbollah fired dozens of projectiles into northern Israel in the morning hours, with some reaching far from the border, the Israeli military said.
Nancy Youssef contributed to this article.
Write to Stephen Kalin at stephen.kalin@wsj.com