An Israeli airstrike on a residential area of the Lebanese capital, Beirut, has killed two top Hezbollah military commanders and other senior officials, in a major escalation that has added to fears of an all-out war.

Hezbollah, the powerful Iranian-backed militia and political group, confirmed the death of Ibrahim Aqil, a senior commander in the group’s elite Radwan forces.

The group also confirmed that Ahmed Wahbi, himself a top Radwan figure, died in the attack that hit the densely populated Dahieh area – a stronghold of the group.

Senior UN official Rosemary DiCarlo warned that the Middle East was at risk of a conflict that could “dwarf” the devastation witnessed in the region so far.

Friday’s attack was another major blow for Hezbollah and the first airstrike to hit Beirut since July, when Fuad Shukr, a right-hand man to leader Hassan Nasrallah, was killed.

It happened just days after a wave of explosions of pagers and walkie-talkies used by the group that killed dozens, wounded thousands more and caused panic in a country already exhausted by almost one year of conflict.

Israel is widely believed to have been behind the attack, but has made no comment.

In Beirut, there were chaotic scenes as emergency teams rushed to the site of the attack on Friday, rescuing the wounded and searching for people believed to be trapped under the rubble.

At least one residential building collapsed and others were heavily damaged. Streets were closed by Hezbollah members, some looking incredulous.

The Lebanese health ministry said at least 31 people were killed in the attack – including three children and seven women – with dozens more wounded.

In a statement, Israel Defense Forces (IDF) spokesman Daniel Hagari said Aqil, a senior commander in Hezbollah’s elite Radwan forces, was killed alongside senior operatives in the group’s operations staff and other Radwan commanders.

Hagari said they “were gathered underground under a residential building in the heart of the Dahiyah neighbourhood [in southern Beirut], hiding among Lebanese civilians, using them as human shields”.

The IDF spokesman added that the individuals killed were “planning Hezbollah’s ‘Conquer the Galilee’ attack plan, in which Hezbollah intended to infiltrate Israeli communities and murder innocent civilians”.

The plan was first reported by the Israeli military in 2018, when the IDF said it was blocking tunnels dug by Hezbollah to penetrate Israeli territory and kidnap and murder civilians.

In April, Washington said it was searching for Aqil, also known as Tahsin, and offered financial rewards to anyone with “information leading to his identification, location, arrest and/or conviction”.

He was wanted by the US because of his links and seniority within Hezbollah, a group that has been proscribed as a terrorist organisation by Israel, the UK, US and other countries.

In the 1980s, Aqil was a member of the group that orchestrated the bombings of the US embassy in Beirut and a marine barracks, killing hundreds of people.

Confirming Aqil’s death in a post on social media, Hezbollah described him as one of its “great jihadist leaders”.

The group was established in the early 1980s by the region’s most dominant Shia power, Iran, to oppose Israel. At the time, Israel’s forces had occupied southern Lebanon during the country’s civil war.

On Saturday, Hezbollah said the second commander to be killed, Wahbi, had “participated in many operations” since the 1980s.

It said Wahbi, 60, held many roles within Hezbollah including “assuming responsibility” for the militant group’s elite Radwan force until early 2024.

Earlier on Friday, Hezbollah said it had launched strikes on military sites in northern Israel. The IDF said 140 rockets were fired into the north of the country, while Israeli police issued warnings about damage to roads.

It came after Israel carried out extensive air strikes on southern Lebanon, saying its warplanes had hit more than 100 Hezbollah rocket launchers and other “terrorist sites” including a weapons storage facility.

The cross-border fighting between Israel and Hezbollah escalated on 8 October 2023 – the day after the unprecedented attack on Israel by Hamas gunmen from Gaza – when Hezbollah fired at Israeli positions in solidarity with the Palestinians.

Since then, hundreds of people, most of them Hezbollah fighters, have been killed in the cross-border fighting, while tens of thousands have also been displaced on both sides of the border.

Israel recently added the return of people displaced from the north of the country to its list of war goals, and Defence Minister Yoav Gallant said on Thursday that his country was entering a “new phase of the war”, concentrating more of its efforts on the north.

After the pager and walkie-talkie explosions across Lebanon earlier this week, there has been a deepened sense of unease in the Middle Eastern country.

It was an unprecedented security breach that indicated how deeply Israel had managed to penetrate the group’s communication system.

Many of the explosions occurred simultaneously, with walkie-talkie explosions on Wednesday occurring in the vicinity of a large crowd that had gathered for the funerals of four victims of Tuesday’s pager blasts.

Hezbollah and Lebanese authorities have blamed Israel for the explosions.

Israeli officials have not commented on the allegations, but most analysts agree that it is behind the attack.

In a televised address on Thursday, Hezbollah leader Hassan Nasrallah said: “The enemy crossed all rules, laws and red lines. It didn’t care about anything at all, not morally, not humanely, not legally.”

Nasrallah vowed a harsh punishment, but indicated his group was not interested in an escalation of its current conflict with Israel.

Lebanese Foreign Minister Abdallah Bou Habbib told the UN Security Council on Friday that Israel had “deliberately undermined” diplomatic efforts for a ceasefire in Gaza and “all attempts of the Lebanese government to de-escalate and exercise self-restraint”.

Israel’s UN envoy Danny Danon said that while his country is not seeking a wider conflict, it “will not allow Hezbollah to continue its provocation”.

UN political affairs chief Rosemary DiCarlo told the Security Council: “We risk seeing a conflagration that could dwarf even the devastation and suffering witnessed so far.”

She added: “I also strongly urge member states with influence over the parties to leverage it now.”

US and UK authorities have urged their citizens not to travel to Lebanon. The White House said it was involved in intense diplomacy to prevent escalation of the conflict along the Israel-Lebanon border.