ISIL managed to penetrate the "security system of the Party of Satan (Hezbollah)...And crush its strongholds...In a first small payment from the heavy account that is awaiting those wicked criminals," according to a statement obtained by US-based SITE Intelligence Group.
Four people died and another 77 were wounded by a suicide car bomb in the Haret Hreik district.
It was the latest strike against the powerful party, whose fighters are aiding Syrian President Bashar al-Assad in a civil war that pits him largely against Sunni Muslims, including ISIL.