Israel’s military says it carried out dozens of air raids across Lebanon targeting Hezbollah after the assassination of the group’s leader Hassan Nasrallah in a southern Beirut suburb.

At least 11 people were killed in an air raid on a house in the town of Ain in the Bekaa Valley in the northeast, according to Lebanon’s National News Agency.

Hezbollah confirmed on Saturday that Nasrallah was killed in an Israeli strike a day earlier in the southern Beirut suburb of Dahiya, dealing a massive blow to the group engaged in fighting with Israel since last October. Hezbollah started firing rockets at Israel in solidarity with Palestinians in Gaza. The group has set a ceasefire in Gaza as a condition to stop its cross-border attacks.

The Israeli military said in a statement on the Telegram messaging app on Sunday that its air forces attacked “dozens of terrorist targets” in Lebanon in the past few hours, hitting “buildings where weapons and military structures of the organisation were stored”.

Al Jazeera’s Imran Khan, reporting from Marjayoun in southern Lebanon, said a civil defence centre was hit in a small town just outside of the Tyre governorate, killing four people and injuring several others.

“Questions are being asked about why this particular fire service unit was actually attacked. It is also affiliated with the Islamic Scout Association, so it has a community centre feel to it,” he said.

“Overnight, we saw several air strikes take place around southern Lebanon. Israel isn’t letting up its pressure at all.”

Israel, which has devastated Gaza in 11 months of relentless bombardment, launched an offensive in Lebanon on Monday after months of deadly border exchanges. Nasrallah’s killing on Friday is a dramatic escalation in the conflict between the two sides.

Israel’s strategy

The Ministry of Public Health said Israeli air raids on Lebanon killed 33 people on Saturday, taking the total number of deaths to more than 700 since the bombardment of Hezbollah strongholds began last week.

A total of 1,640 people have been killed in Lebanon since October 8, including 104 children and 194 women, the majority in Israeli strikes in the past two weeks.

The killing of Nasrallah, who led Hezbollah for more than 30 years and built the Lebanese group into a powerful force, is one of the heaviest blows ever dealt by Israel to Hezbollah.

Al Jazeera’s Zeina Khodr reporting from Beirut said Hezbollah is at a turning point, “both at an organisational level and at the popular level”.

“There is no doubt that Hassan Nasrallah was considered arguably the most powerful man in Lebanon even though he did not hold public office,” she said. “Hezbollah needs to prove that its command and control structure is intact, that its leadership is still able to function.

“What Israel has been doing, its strategy has been to dismantle Hezbollah’s leadership.”

An Israeli invasion of Lebanon?

Israel has hinted at launching a ground incursion into Lebanon as its army chief Herzi Halevi said on Saturday that his forces were prepared for what was to come and Lebanese residents were told to flee to safety. Nearly a million people have fled southern Lebanon amid Israeli bombardment.

Speaking for the first time since the assassination of Nasrallah, Israeli Prime Minister Benjamin Netanyahu said there are now two war goals for northern Israel bordering Lebanon.

The first is to return evacuated Israelis back to those towns and settlements in the north. The second is to restore the balance of power on the northern border, Al Jazeera’s Hamdah Salhut reported.

“Israeli officials were saying all day on Saturday that they are determined to destroy Hezbollah and destroy all of its military capabilities. The Israeli army chief of staff, along with Israel’s Defence Minister Yoav Gallant, have approved new plans for offensive strategies in the north,” Salhut said.

“This comes amid fears of a looming ground invasion into southern Lebanon – something that is causing a lot of fear on both sides of the border.”

Meanwhile, United States President Joe Biden said on Saturday that it was time for a ceasefire.

Asked by reporters in Rehoboth Beach, Delaware if an Israeli ground incursion into Lebanon was inevitable, Biden responded: “It’s time for a ceasefire.”

Asked if the US would respond to missile attacks on its warships in the Red Sea, Biden said: “We’re responding.”

Reporting from Washington, DC, Al Jazeera’s Shihab Rattansi said Biden’s statement raises several questions.

“When he says he’s for a ceasefire, does he mean a complete ceasefire? Does he accept what Hezbollah has long said – that if Israel stops the destruction of Gaza, then residents of northern Israel can return to their homes? Or is he accepting the argument from Israel that the only way to de-escalate is to escalate? Reportedly, there are proponents of that strategy in the administration,” Rattansi said.

“We have heard that the administration is against an Israeli invasion of southern Lebanon but then consistently we have heard the administration say that it’s against actions that Israel subsequently does.”

On Friday, Yemen’s Houthi rebels claimed attacks on the Israeli cities of Tel Aviv and Ashkelon, as well as three US Navy warships, with missiles and drones.

The Houthis have repeatedly fired at Israel and have carried out numerous attacks on Israeli-linked ships in the Red Sea, the Gulf of Aden and the Bab al-Mandeb Strait since November in what they describe as a campaign of solidarity with Palestinians under Israeli attack in Gaza.