Israel killed a top Hezbollah commander and other senior figures in the Lebanese movement in an airstrike on Beirut on Friday, vowing to press on with a new military campaign until it is able to secure the area around the Lebanese border.

The Israeli military and a security source in Lebanon said Ibrahim Aqil had been killed with other senior members of an elite Hezbollah unit in the airstrike, sharply escalating the year-long conflict between Israel and the Iran-backed group.

Hezbollah confirmed Aqil's death in a statement just after midnight that called him "one of its top leaders," without providing details of how he died.

In a later statement summarising Aqil's biography, Hezbollah said he was killed in Beirut's southern suburbs of Dahiyeh in what it called a "treacherous Israeli assassination".

Lebanon's health ministry said at least 14 people died in the strike and the toll was expected to climb as rescue teams worked through the night. It was not immediately known whether the toll included Aqil and other Hezbollah commanders.

Earlier, the ministry said at least 66 people were injured, nine of whom were in critical condition.

A second security source said at least six other Hezbollah commanders died when multiple missiles slammed into the opening of a building's garage. The explosion tore into the building's lower levels as Aqil met other commanders inside.

Witnesses reported hearing a loud whistling and several consecutive blasts at the time of the strike.

In a brief statement carried by Israeli media, Prime Minister Benjamin Netanyahu said Israel's goals were clear and its actions spoke for themselves.

The strike inflicted another blow on Hezbollah after two days of attacks in which pagers and walkie-talkies used by its members exploded, killing 37 people and wounding thousands. Those attacks were widely believed to have been carried out by Israel, which has neither confirmed nor denied its involvement.

Local broadcasters showed groups of people gathered near the site, and reported they were searching for missing people, most of them children. Drones were still flying over Beirut's southern suburbs hours after the strike.

"We are not afraid, but we want a solution. We cannot continue with the country like this," said a Lebanese citizen who spoke to Reuters. "War? I don't know if it started or not, but nothing is reassuring. It is clear that the two sides will not stop."

The U.N. Special Coordinator for Lebanon, Jeanine-Hennis Plasschaert, said Friday's strike in a densely populated area of Beirut's southern suburbs was part of "an extremely dangerous cycle of violence with devastating consequences. This must stop now."

The strike marked the second time in less than two months that Israel has targeted a leading Hezbollah military commander in Beirut. In July, an Israeli airstrike killed Fuad Shukr, the group's top military commander.