BERIUT — Reports of new casualties streamed in across Lebanon on Sunday, from the south to the far north. Families displaced by Israeli strikes found shelter where they could. The gloomy capital smelled of sulfur and drones buzzed overhead, one resident wrote.

“War is here, in every aspect of our lives,” Mona Fawaz, a professor at the American University of Beirut, said in her post on X, capturing the mood of a country used to uncertainty but now settling into dread.

Israel’s escalating military offensive, including Friday’s assassination of Hezbollah leader Hasan Nasrallah, has set off a sprawling humanitarian disaster here, with fears of a possible ground invasion still to come.

After years of economic and political crisis, Lebanon now faces catastrophe. More than 1,000 people have been killed in the last two weeks and hundreds of thousands have been displaced. The hospitals are filled with the wounded and shelters are over capacity.

Israel dramatically expanded the scope and pace of its operations over the last week - largely contained to the south over the last 11 months - pummeling communities in the northeast and in Beirut while moving more troops and equipment to the border.

With hardship deepening and relief in short supply, there are growing fears of unrest in a country that has never fully recovered from its civil war. Accusing Israel of sowing internal division, Lebanon’s army urged people in a statement Sunday to “uphold national unity and refrain from participating in actions that could jeopardize civil peace during this precarious and critical juncture in our nation’s history.”

The Israeli airstrikes that killed Nasrallah in an underground bunker on Friday leveled apartment blocks in Beirut’s southern suburbs, which have long been synonymous with Hezbollah’s civic and military strength. Hours later, the Israel Defense Forces began issuing evacuation orders for the area, home to some 400,000 people, and in the days since has carried out multiple rounds of strikes on buildings it said were being used to store munitions.

The streets there are desolate now. Shops are closed and the sites of some strikes are still smoldering. The first evacuation orders came in the middle of the night Friday, sparking a chaotic civilian rush through darkened streets.

“I didn’t know which of my children to pick up,” said Reem, a mother of five who fled with her family on foot. Like others in this story, she spoke on the condition she be identified only by her first name, fearing reprisals by Hezbollah.

Reem and her husband didn’t know where to go. They had only made it a few blocks when another airstrike hit, she said. It sounded close, so they doubled back. “I thought we would die,” she said.

Eventually the family made it to a main road, joining a sea of parents, grandparents and children moving north toward downtown Beirut. They spent the night on the corniche, normally reserved for scenic strolls, looking out at the darkness of the Mediterranean Sea.

Other families sheltered on patches of grass beside busy roads or laid out thin sheets on the edge of a basketball court.

The city has already absorbed multiple waves of people fleeing airstrikes. Hotels were quickly booked up last week after Israeli evacuation orders in the east and south. There are few apartments available to rent, and prices for an empty room are soaring.

In Beirut’s western Rawshah neighborhood Saturday, another displaced family was calling every number they could think of, hoping to find shelter. They’d spent the previous night on the curb beside a line of parked cars; when the sun came up they moved to the shade of a tree growing in the median.

“Never in my life have I experienced this,” said Hind, 57, who was helping her daughter-in-law, Zainab, with her four children, including her newborn son, crying in her arms. He was hungry, Zainab said, but she couldn’t find a place to breastfeed and had forgotten to bring formula when they fled.

“My son is from Hezbollah and even he can’t find a place” to stay, said Hind. “If I knew we would be humiliated like this, I would have preferred to die in my home.”

Lebanon was paralyzed by political and economic troubles even before Hezbollah began firing on Israel in October in solidarity with Hamas in Gaza. Between 2019 and early 2023, its currency lost more than 98 percent of its value, according to the World Bank; nearly 45 percent of people live below the poverty line. And the country has been without a president since 2022, led by a caretaker government with limited power and public credibility.

The state had been on the verge of “disappearing,” said Nizar Ghanem, director of research at the Alternative Policy Institute in Beirut. In the wake of Nasrallah’s killing, the country has entered what he called a “liminal phase.”

“People feel a state of defeat” and are saying it “echoes 1967 in the scale of the blow,” he said, referring to Israel’s victory over a coalition of Arab armies in the 1967 war.

Without a diplomatic compromise, he said “Lebanon will be destroyed completely in a massive war.” The panic and despair extends well beyond Beirut. By Friday, at least 15,000 people had fled to Zahle, a Christian town in the eastern Bekaa Valley.

The wealthier ones had found rooms at hotels, others were in schools converted into shelters, some were sleeping in parks. “The Shia come to Christian towns for safety,” the town’s mayor, Assaad Zgheib, said in an interview in his office.

“But are they safe? Are we safe? We don’t know,” he said.

The municipality was poorly equipped to handle the influx, its assets decimated, like other towns, by Lebanon’s financial crisis. Private companies and aid groups had stepped in to help, and part of the response was being handled capably by the Health Ministry, led by Firass Abiad, a respected doctor, he said: “In Lebanon it depends on the person. It is not a country of institutions.”

Many in the town had welcomed the displaced, he said, but others feared who might be coming, including members of Hezbollah whose presence could endanger the town. “I cannot tell anyone you cannot come,” said Zgheib. “We cannot say we only receive women and children.” Fighters should stay away, he urged, to “save his family and his neighbors.”

The IDF has said it trying to minimize civilian casualties, but its strikes were not discriminating between Hezbollah members and those they lived with, the mayor said, and its plans for Lebanon were unclear. “You have to ask them what’s going to happen to us,” said Zgheib.

Ali Elbawi, 44, fled with his family from Saraain, spending a night on the streets before they were told to come to one of Zahle’s school shelters. His family was now separated - his father in one school, a sister and brother in another, his three children sent to Beirut. He and his wife stayed in a classroom with four people. There was food, but no showers.

In his village, the Israelis “destroyed houses” for “no reason,” he said. “Not every house destroyed is from Hezbollah,” he said. “I am not Hezbollah.” Children played on a battered basketball hoop in a courtyard, as volunteers distributed food. “We hope to finish this war,” Elbawi said. “We hope.”

At a hospital eight miles away, in Rayak, Mohammad Abdullah, the hospital’s chief executive, said Friday that staff had started sleeping at the facility to deal with the influx of patients. Four-hundred injured people had arrived over the previous 10 days, including nearly 200 on Monday and Tuesday, when Israel escalated its bombing campaign. “All of them civilians,” he said, speaking of the arrivals last week.

In an upstairs ward, Mohamad Moussawi, 8, recovered from a strike near his home in Nabi Chit that also injured his two younger siblings. Shrapnel had torn through the tendons in his right hand, which was wrapped in a bandage, his fingers bloated and blue. His father, Ali Moussawi, a taxi driver, said the family was fortunate that the hospital had given them an entire room. They had nowhere else to go.

In a park in Zahle wedged in the middle of a boulevard, a family of six from Baalbek sheltered near a tree. They had fled there on Monday, when the bombing around them was constant, said the father, Abdullah Sweidan, so intense that one of his sons had stopped speaking.

They spent the days in the park, and slept, all six of them, in a red tuk-tuk that they had borrowed from friends. Other families were scattered under trees. “Who knows,” when they would return, said Sweidan. “Who knows anything.”