Lebanon's Hezbollah said early on Wednesday its senior commander Fuad Shukr was in the building in the southern suburbs of Beirut targeted by an Israeli strike, but it did not confirm his fate.

Israel's military announced late on Tuesday it had killed Shukr, whom it named as Hezbollah's most senior commander and blamed for an attack at the weekend that left a dozen youths dead in the Israeli-occupied Golan Heights.

Hezbollah has denied any involvement in the weekend attack.

Israeli Defence Minister Yoav Gallant said Shukr "has the blood of many Israelis on his hands. Tonight, we have shown that the blood of our people has a price, and that there is no place out of reach for our forces to this end."

A senior security source from another country in the region confirmed that Shukr had died of his wounds.

Hezbollah's long-awaited statement on Wednesday said Israel had attacked a residential building in the southern suburbs of Beirut, a stronghold for the group, and that "a number of citizens" had been killed and others wounded.

It said Fuad Shukr "was present in this building at the time," but that the group was still waiting for definitive results on his fate.

On Wednesday morning, Lebanon's civil defence teams were on the ground in the southern suburbs, known as Dahiyeh, clearing rubble from the strike, according to a Reuters witness.

Hezbollah set up a security cordon around the area but granted limited access to reporters to film.

The attack appeared to have shorn off the top corner of a multi-storey building and scattered bits of charred debris onto the surroundings buildings and streets.

There were no other residents in sight.

The Israeli strike killed a woman and two children, medical and security sources told Reuters late Tuesday.

Shukr was an adviser to Hezbollah leader Sayyed Hassan Nasrallah, according to Hezbollah sources and to the Israeli military's announcement of his killing.

His apparent killing marks the most senior Hezbollah commander to have been killed in nearly 10 months of exchanges of fire between the Israeli military and Hezbollah, taking place in parallel with the Gaza War.