Mustafa Amine Badreddine, a top commander of Lebanon-based Shia militant organisation Hezbollah died in an Israeli air strike near Damascus airport on Tuesday, reported the BBC citing Lebanon's al-Mayadeen TV.
Israel is yet to comment on the claim of his death. Badreddine and three of his accomplish are accused of assassinating former Lebanese PM Rafik Hariri in Beirut in 2005.
Badreddine, born in 1961 and a senior figure in Hezbollah's military wing, took part in most of the operations of the Islamic resistance since 1982," said Hezbollah announcing his death.
He reportedly served as an adviser to the group's overall leader Hassan Nasrallah.
Hezbollah - the Party of God - is a Shia Islamist political, military and social organisation that wields considerable power in Lebanon.
Hi death has come as biggest blow to the group since the CIA-aided 2008 assassination of its military commander Imad Mughniyah.