"The assassination of Hajj Hassan Lakkis is not one of those passing incidents between us and the Israelis and nobody should think that," Nasrallah said in a televised speech during the commemoration ceremony of Lakkis in Beirut's southern suburbs.

“Israelis should not think that Hezbollah is too busy with the situation in the region and in Lebanon and that the timing is not right for us because – this [kind of thinking] would be a mistake," he added.

"We have an open-ended account to settle with Israel and the killers will be punished sooner or later and the blood of our martyrs will never split in vain," the Hezbollah chief said.

Lakkis was gunned down earlier this month outside his home south of Beirut.

The party has warned that Israel will bear full responsibility for the assassination.

“The punishment is forthcoming,” Nasrallah warned.

The last time a top Hezbollah leader was assassinated was in 2008, when Imad Mughniyeh was killed in a Damascus car bomb blast.

Mughniyeh's killing was also blamed on Israel, Hezbollah's sworn enemy, which denied involvement.

SHI/SHI