Hezbollah’s leader for the past 32 years, Hassan Nasrallah, has been killed in an Israeli air strike on Lebanon’s capital Beirut on Friday evening.

Ali Karki, the commander of Hezbollah’s southern front, and other Hezbollah commanders were also killed in the massive air attack on Beirut’s southern suburb of Dahiyeh, the Israeli military claimed.

Just more than a week ago, Israel also killed senior Hezbollah commander Ibrahim Aqil in Beirut. These events come just two months after Hamas’s political bureau chief, Ismail Haniyeh, was killed by Israel in Iran.

The deaths of Nasrallah and other leaders in these unprecedented attacks on Lebanon and during the mass detonation of pagers and handheld radios belonging to Hezbollah commanders earlier this month have left the group facing a potential power vacuum.

Israel has claimed this as a huge victory, but observers fear an escalation in the conflict between Israel and Iran, backs Hezbollah. So what will happen next?

Who was Hassan Nasrallah?

Nasrallah, 64, became Hezbollah’s third secretary-general in 1992, after his predecessor, Abbas al-Musawi, was killed by Israeli missiles.

Hezbollah (Party of God in Arabic) is an Iran-backed group formed in 1982 to fight Israel’s occupation of southern Lebanon. It finds most of its support among Shia Muslims.

Nasrallah reached the peak of his popularity in Lebanon and beyond in 2006 after a war with Israel. His speeches, which combined political and religious elements, also contributed to his widespread appeal.

Critics, however, have also viewed Nasrallah as a leader of a Shia party fighting for Iranian interests, particularly after he sent fighters to help crush a 2011 uprising in Syria against Iran’s ally, President Bashar al-Assad.

Since Israel’s war on Gaza began in October 2023, Nasrallah has given televised speeches extending support for Hamas, while Hezbollah has exchanged cross-border missiles with Israel. In his last speech on September 19, he addressed the pager attacks in Lebanon.

What do we know about Israel’s attack on Nasrallah?

On Friday evening, Israel carried out a wave of air raids on the densely populated Haret Hreik neighbourhood in Dahiyeh, southern Beirut. These continued through to early on Saturday, forcing thousands of residents to flee the area.
On Saturday, Israeli forces said they had targeted Hezbollah’s headquarters and killed Nasrallah.
Following hours of speculation, Hezbollah confirmed Nasrallah’s death.
At least 11 people were killed and 108 wounded in the attacks, according to Lebanon’s Ministry of Public Health.
Israel media says about 85 so-called “bunker-buster” bombs were used in Friday’s attack. Also known as “ground penetration munition”, these missiles burrow deep into the ground before they detonate and weigh between 2,000 to 4,000 pounds (900-1,800kg) each. The Geneva Convention has outlawed their use in densely populated areas. Dahiyeh is a densely packed Beirut neighbourhood, and the Israeli missiles flattened multiple residential buildings.

Who will succeed Nasrallah and how will this be decided?

Hezbollah’s seven-to-eight-member shura council is expected to convene to decide who will now lead the party.

Hashem Safieddine, head of Hezbollah’s executive council, is believed to be among the choices as the group’s new secretary-general.

As executive council head, Safieddine oversees Hezbollah’s political affairs. He also sits on the Jihad Council, which manages the group’s military operations, and is Nasrallah’s maternal cousin.

Following Israel’s recent pager explosions, Safieddine said Israel had initiated a “new confrontation” and the response to the attack would be a “special punishment”.

How has Hezbollah responded to the latest attacks?

In a statement on Saturday, in which it confirmed the death of Nasrallah, Hezbollah said it would continue its military operation in support of Gaza and the defence of Lebanon.

It launched five rocket attacks into northern Israel following the announcement that Nasrallah had been killed, according to Al Jazeera correspondent Imran Khan, reporting from Marjayoun, Lebanon.

Will Nasrallah’s killing weaken Hezbollah?

While Hezbollah has been hit hard in the short term, analysts say it is unlikely that the group will be badly affected in the long run as one leader can be replaced with another and the group maintains its vast military arsenal and strength.

Beirut is considered to be Hezbollah’s “weakest point” as it is also where Western embassies and people who are affiliated with Western intelligence agencies are, said Mohammad Marandi, ‏‏a professor at the University of Tehran. Overall, however, “Israel does not have the capability to defeat Hezbollah militarily”, Marandi told Al Jazeera.

Analysts say the group now faces strategic choices amid a temporary leadership vacuum rather than a full blow to its survival.

“Hezbollah is not going to disappear,” said Yezid Sayig, senior fellow at the Carnegie Middle East Programme. It will “exercise strategic patience” even if Iran does not sweep in to defend them now, he added.

Experts do believe, however, that Hezbollah has made other mistakes that have weakened it relative to Israel.

“The big mistake that Hezbollah has made is to allow the Iranians to use them too much as a proxy,” said Sultan Barakat, senior professor in public policy at Hamad Bin Khalifa University. “Hezbollah were very effective when they fought for the liberation of the Lebanese land – for their own people.”

For the last year, however, Iran has given them little agency around how to use weapons they were given, while the group has miscalculated how much violence Israel is willing to exert, not just on the people of Gaza, but on the Lebanese people as well, he told Al Jazeera.

Is this a win for Israel?

At the UN General Assembly in New York on Friday – before the latest strikes – Israeli Prime Minister Benjamin Netanyahu had one main message when he told members: “We are winning.” Israel is claiming this devastating assault on Hezbollah as a major victory.

Experts largely agree that Israel will continue on the offensive.

“Israel views it has momentum on its side following Nasrallah’s death and would want to take maximum advantage of a leadership vacuum,” Ali Rizk, a security and policy analyst, told Al Jazeera on Saturday.

The perceived success of its assault on Hezbollah may also sway domestic public opinion in Netanyahu’s favour, according to Mohamad Elmasry at the Doha Institute of Graduate Studies.

“Israelis who were opposing Netanyahu were opposed to his failures in Gaza, not being able to eliminate Hamas and not being able to bring hostages home, but they were not an antiwar crowd,” Elmasry said.

However, Israel may not necessarily achieve its stated goals of eliminating resistance and creating calm. In the past, escalated attacks have worked against them by breeding more resistance and opposition to Israel, Elmasry told Al Jazeera.

A continued offensive would also require continued supply of American ammunition, according to Elijah Magnier a military analyst in Brussels. In his first statement after the assassination, US President Joe Biden said Washington supported Israel’s military strikes against Hezbollah, and described Nasrallah’s killing as “justice” for hundreds of Americans he accused Hezbollah of killing.

How will Iran respond?

While Nasrallah’s killing has added to fears of an Iranian response, experts say the country now faces an even more delicate balancing act between standing up to Israel and avoiding a spillover of war in the region.

“Iran will probably not opt for an all-out escalation,” said Rizk. He added that the country will likely continue its usual approach of “fighting via proxies, including allies in Iraq and Yemen” before entering into any direct confrontation with Israel.

Iranian President Masoud Pezeshkian issued a statement on the killing of Nasrallah on Saturday, saying it “will only further strengthen the resistance”.

He added that the international community will not forget that the order for this “terrorist attack” was issued from New York, likely referring to Netanyahu’s presence at the United Nations General Assembly on Friday.

Pezeshkian also said the United States cannot deny complicity in Nasrallah’s killing as it has continued to supply weapons and military aid to Israel since the war on Gaza began nearly one year ago.