Israeli Prime Minister Benjamin Netanyahu has said targeting Hezbollah leader Hassan Nasrallah was “an essential condition to achieving the goals we set”.
Hezbollah confirmed on Saturday that one of its founding members, who has been linked by Israel to attacks on Israeli and Jewish targets, had been killed in an airstrike in southern Beirut.
The Israeli military said it carried out a precise airstrike on Friday while Hezbollah leaders were meeting at their headquarters in Dahiyeh, south of Beirut.
In his first public remarks since the killing, Mr Netanyahu said: “He wasn’t another terrorist. He was the terrorist.”
He said Mr Nasrallah’s killing would help bring displaced Israelis back to their homes in the north and would pressure Hamas to free Israeli hostages held in Gaza.
But with the threat of retaliation high, he warned the coming days would bring “significant challenges” and warned Iran against trying to strike.
“There is no place in Iran or in the Middle East that Israel’s long arm cannot reach. And today you know how much that is true,” he said.
The Lebanese Health Ministry said six people were killed and 91 injured in the strikes which hit six apartment buildings.
Ali Karki, the commander of Hezbollah’s Southern Front, and other commanders were also killed, the Israeli military said.
A statement from Hezbollah said Mr Nasrallah — who led the group for more than three decades — “has joined his fellow martyrs”.
The group vowed to “continue the holy war against the enemy and in support of Palestine”.
Iran’s supreme leader announced five days of public mourning and Ayatollah Ali Khamenei called Mr Nasrallah “the flag-bearer of resistance” in the region.
Hundreds of protesters took to the streets of Tehran, waving Hezbollah flags and chanting “Death to Israel” and “Death to Netanyahu the murderer”.
Iran’s UN ambassador Amir Saeid Iravani wrote to the heads of the United Nations and the Security Council on Saturday calling for an emergency council meeting over the attack.
He warned Israel not to attack any of its diplomatic or consular premises, or its representatives.
“Iran will not hesitate to exercise its inherent rights under international law to take every measure in defense of its vital national and security interests,” Mr Iravani wrote.
Israel’s Chief of Staff Lieutenant General Herzi Halevi said on Saturday that the killing was “not the end of our toolbox”, indicating that more strikes were planned.
Defence minister Yoav Gallant called it “the most important targeted strike since the founding of the State of Israel”.
Late on Saturday, Mr Gallant’s office said he was meeting with top army commanders to discuss the expansion of military activities along Israel’s northern front.
The military said it was mobilising three more battalions of reserve soldiers to serve across the country. It already sent two brigades to northern Israel to prepare for a possible ground invasion.
Israeli military spokesman Lieutenant Cololnel Nadav Shoshani said Israel has inflicted heavy damage on Hezbollah’s capabilities over the past week by targeting immediate threats and strategic weapons, such as larger, guided missiles.
But he said much of Hezbollah’s arsenal remains intact and that Israel would continue to target the group.
Air raid sirens sounded across central Israel on Saturday afternoon, including at the Tel Aviv international airport, shortly after Mr Netanyahu returned from a trip to the US.
The Israeli military said it intercepted a missile launched from Yemen. Houthi rebels based in Yemen later said they were behind the attack targeting Ben Gurion Airport.
The Israeli military updated guidelines for Israeli citizens, cancelling gatherings of more than 1,000 people due to the threat.
On Saturday morning, the Israeli military carried out more than 140 airstrikes in southern Beirut and eastern Lebanon’s Bekaa Valley, including targeting a storage facility for anti-ship missiles in Beirut suburb of Dahiyeh.
Israel said the missiles were stored beneath civilian apartment buildings. Hezbollah launched dozens of projectiles across northern and central Israel and deep into the Israel-occupied West Bank, damaging some buildings in the northern town of Safed.
The Israeli army again warned Lebanese residents to stay away from Hezbollah combat equipment and facilities, including in the southern suburbs of Beirut and southern Lebanon. The US State Department issued an alert urging American citizens to leave the country.
A total of 1,030 people — including 156 women and 87 children — have been killed in Israeli strikes in Lebanon in less than two weeks, the country’s health minister said on Saturday.