Israel’s military carried out more strikes Tuesday against Hezbollah targets in Lebanon, including in the densely populated neighborhoods south of Beirut, after hundreds of people were killed the previous day in the deadliest barrage of Israeli attacks there in decades.

One strike Tuesday near Beirut, in an area known as Dahiya where Hezbollah is the dominant power, hit a six-story building, according to Lebanon’s state-run news agency, and sent a plume of smoke above the Lebanese capital.

Lebanon’s Health Ministry said six people had been killed and 15 others injured.

The Israeli military claimed the strike had killed Ibrahim Kobeisi, identified as a senior Hezbollah commander who oversaw Hezbollah’s missile apparatus. Hezbollah did not immediately comment on the claim.

Hezbollah also continued to fire at northern Israel, but most of the rockets were intercepted as sirens and explosions were heard in several communities. The strikes have unnerved the Middle East, sparking fears of an all-out war between Israel and Iran-backed Hezbollah as the fighting in the Gaza Strip continues with no clear prospect of a truce.

Prime Minister Benjamin Netanyahu told Israelis that they were headed into “complicated days.”

The military said Israeli warplanes struck 1,600 Hezbollah targets Monday, destroying cruise missiles, long- and short-range rockets and attack drones, including weapons concealed in private homes. Israel estimates Hezbollah has 150,000 rockets and missiles, including guided missiles and long-range projectiles capable of striking anywhere in Israel.

The Israeli military says it has no immediate plans for a ground invasion but is prepared for one, after moving thousands of troops serving in Gaza to the northern border. It says Hezbollah has launched 9,000 rockets and drones into Israel since last October, including 250 Monday.

Israel has responded with increasingly heavy airstrikes and the targeted killing of Hezbollah commanders while threatening a wider operation.

Lebanon’s health minister raised the two-day death toll from the Israeli strikes to 564 people, with another 1,800 injured, making Monday the country’s deadliest day since a civil war that ended in 1990. The Health Ministry’s figures do not distinguish between civilians and combatants, although Health Minister Firass Abiad, said Tuesday that scores of women and children were among those killed.

“The overwhelming majority of those who fell during the attacks that happened yesterday, they were safe and unarmed people in their homes,” he said.

It’s a staggering toll for a country still reeling from a deadly pager and walkie-talkie attack the week before. Lebanon blamed those attacks on Israel, but Israel did not confirm or deny responsibility.

Panicked by the scope and intensity of the airstrikes, civilians fled southern Lebanon and sought the relative safety of Beirut, clogging the roads leading into the capital.

Displaced families slept in shelters hastily set up in schools in Beirut and the coastal city of Sidon.

With hotels quickly booked to capacity or rooms priced beyond the means of many families, those who did not find shelter slept in their cars, in parks or along the seaside.

Issa Baydoun fled the village of Shihine in southern Lebanon when it was bombed and came to Beirut in a convoy of cars with his extended family. They slept in the vehicles on the side of the road after discovering that the shelters were full. “We struggled a lot on the road just to get here,” he said.

Baydoun rejected Israel’s contention that it hit only military targets. “We evacuated our homes because Israel is targeting civilians and attacking them,” he said. “That’s why we left our homes, to protect our children.”

The U.N. High Commissioner for Refugees in Lebanon said Tuesday that one of its staffers and her son were among those killed Monday in the Bekaa region, while a UNHCR-contracted cleaner was killed in a strike in the south. The husband of a staffer and one of her children were wounded.

Well-wishers offered up empty apartments or rooms in their houses in social media posts. Volunteers set up a kitchen to cook meals for the displaced at an empty gas station that first became a hub for volunteers after the city’s devastating 2020 port explosion.

In the eastern city of Baalbek, the state-run National News Agency reported that lines formed at bakeries and gas stations as residents rushed to stock up on essential supplies in anticipation of another round of strikes.

The border crossing with Syria saw traffic jams as a result of people escaping from Lebanon to the neighboring country.

The pace of Israeli strikes appeared to surpass that seen during the 2006 war between Israel and Hezbollah, in which more than 1,000 Lebanese people were killed over a month.

The sides appear on the verge of war again after tensions have escalated over the last 11 months. Hezbollah has been firing rockets, missiles and drones into northern Israel in solidarity with the Palestinians and its ally Hamas, a fellow Iran-backed militant group, in Gaza.

Hezbollah is the strongest political and military actor in Lebanon and is considered the top paramilitary force in the Arab world.

Associated Press contributed.