Hassan al-Laqis, the senior Hezbollah commander shot dead outside his home in Lebanon Wednesday, had taken part in Syria's civil war and was previously the target of several failed assassination attempts.
Hezbollah described Laqis as "one of the leaders of the Islamic resistance" against Israel.
He had been with the Shi'ite militant group since it was set up in the 1980s with Iranian support to fight Israeli troops occupying south Lebanon. His son was killed in the group's 34-day war with Israel in 2006.
Laqis was the most senior Hezbollah figure to be assassinated since Imad Mughniyeh was killed in a Damascus bombing in 2008.
Hezbollah has blamed Israel for both killings, a charge Israeli officials deny.