Nawar al-Saheli, a Hezbollah member of Lebanon's parliament, accused Israel on Friday of being responsible for the death of their top commander, Mustafa Amine Badreddine, and called the strike "and open war."
"We do not want to get ahead of the investigation, but there is no doubt that Israel was behind his death," the MP told Hezbollah-controlled TV station Al-Manar.
"The resistance will carry out its duties at the appropriate time," he added.
Israel has declined to comment on the allegations.
Hezbollah has not publicly placed blame on Israel, nor revealed details of Badreddine's death.