Israel's army said it had killed the cleric tipped to succeed slain Hezbollah leader Hassan Nasrallah in an air strike on Beirut three weeks ago that targeted commanders of the Iran-backed group.

Hezbollah has not issued a statement about the Israeli claims to have killed Hashem Safieddine.

"It can now be confirmed that in an attack approximately three weeks ago, Hashem Safieddine, the head of Hezbollah's Executive Council, and Ali Hussein Hazima, the head of Hezbollah's Intelligence Directorate, were killed along with other Hezbollah commanders," the Israeli army said in a statement Tuesday.

The army said the air force had hit Hezbollah's main intelligence headquarters in the southern Beirut suburb of Dahiyeh, Hezbollah's stronghold in the Lebanese capital, and that more than 25 Hezbollah fighters were present at the time.

Longtime Hezbollah leader Nasrallah was killed on September 27 in an Israeli air strike on Beirut's southern suburbs.

Safieddine, tipped to succeed his distant cousin as leader of the Lebanon-based group, had been out of contact since Israeli strikes on Beirut weeks ago, a high-level Hezbollah source said at the time.

"We have reached Nasrallah, his replacement and most of Hezbollah's senior leadership", Israeli army chief Lieutenant General Herzi Halevi said in a statement after the confirmation of Safieddine's death.

After nearly a year of war with the Palestinian Islamist movement Hamas in Gaza, Israel shifted its focus to Lebanon in late September, vowing to secure its northern border threatened by cross-border fire from Hamas's Lebanese ally.

Israel ramped up its air strikes on Hezbollah strongholds around the country and sent in ground troops late last month, in a war that has killed at least 1,552 people since September 23, according to an AFP tally of Lebanese health ministry figures.

Agence France-Presse