A military commander from Hezbollah was gunned down in front of his home in south Beirut, the group said in a statement on Wednesday.
Hezbollah did not say how Hassan Laqis was killed, but Lebanese media reports said he was shot in the building's parking lot, just outside the security perimeter the group keeps around its headquarters.
“Around midnight on Tuesday, one of the commanders of resistance, Hassan al-Laqis, was assassinated in front of his house in the Saint Therese district as he returned from work,” Hezbollah said in a statement.
Hezbollah immediately blamed Israel for the killing. “The direct accusation falls on the enemy Israel," the group alleged. Israeli officials denied any involvement.
The New York Times noted Hezbollah has been careful to avoid blaming Sunni militants for violent attacks like the one that killed Laqis, for fear of further inflaming sectarian tensions already destabilizing the country.
Though Israel has been implicated in the killing of its arch-enemy Hezbollah before, sectarian tensions in Syria and Lebanon support theories that radical Sunnis may be behind the killing instead.
A recent bombing at the Iranian Embassy in Beirut was alleged to have been the work of militant Islamists affiliated with Sunni Syrian rebels.
It is unclear what exact role Laquis played in Hezbollah, given the organization's secrecy. But he is believed to have been among its most senior military leaders.