Hezbollah said Aqil, "one of its great leaders", had been killed "on the road to Jerusalem", the phrase it uses to refer to fighters killed by Israel.

AFP journalists at the scene said the blast left a massive crater and gutted the lower floors of a high-rise building in the Lebanese capital's southern suburbs.

Rescue workers were still using heavy equipment to search the rubble hours after the strike, AFPTV footage showed.

Aqil's assassination was the second of a senior Hezbollah commander since the start of Israel's war on Gaza. An Israeli strike on Beirut in July killed Fuad Shukr, a top operations chief for the movement.

It also followed two waves of explosions, on Tuesday and Wednesday, that saw Israel detonate communication devices used by Hezbollah members.

Those blasts killed dozens, including civilians and left Lebanon in a state of shock over the attack that saw Hezbollah members killed in civilian-packed areas.

Stephane Dujarric, spokesman for UN Secretary-General Antonio Guterres, said the body was "very concerned about the heightened escalation" and called for "maximum restraint" from all sides.

A source close to Hezbollah said Aqil was "at a meeting with commanders" when he was killed.

Lebanon's health ministry said that the attack killed at least 14 people and wounded 66 more, and that it expected more bodies to be found.

Israeli troops and Hezbollah fighters have battled each other along the Israel-Lebanon border since Israel's war on Gaza erupted in October.

The focus of Israel's firepower for nearly a year has been on Gaza, but as it Israel has failed to achieve any of its war goals, the focus of the war has moved to Israel's northern border.

Months of near-daily border clashes have killed hundreds in Lebanon, including civilians, and dozens in Israel, forcing tens of thousands on both sides to flee their homes.

In Gaza, Israel's relentless bombardment and ground invasion have killed at least 41,272 people, according to the territory's health ministry. The UN Human Rights office says most of the dead are women and children.

*This story was edited by Ahram Online.