In a statement on Wednesday, Hezbollah confirmed that Mohamed Naim Nasser had been martyred, Press TV reported.
It did not provide details about the circumstances of the assassination.
Reports said earlier in the day that Israel killed the commander in an air raid on the Hosh area in Tyre.
In response to the assassination, Hezbollah said its fighters launched “100 Katyusha rockets” targeting two Israeli positions in the occupied Golan Heights. It was, the statement said, part of Hezbollah’s “response to the attack and assassination that the enemy carried out.”
Two security sources told Reuters news agency that the assassinated commander was responsible for a section of Hezbollah’s operations at the border, where the group and Israeli forces have been fighting since October.
As tensions continue to escalate, Israel's minister of military affairs Yoav Gallant once again threatened “to take any action required in Lebanon, or to reach an arrangement from a position of strength.”
The exchange of fire has intensified since Israel assassinated senior Hezbollah commander Sami Taleb Abdullah in June. That assassination prompted Hezbollah to fire its largest barrages of drones and rockets against Israeli targets yet in retaliation.
Hezbollah has made it clear that a comprehensive ceasefire in the Gaza Strip is the sole way to bring calm to the Lebanese border.
Hezbollah has fought off two Israeli wars against Lebanon in 2000 and 2006. The resistance movement forced the regime to retreat in both conflicts.
MNA/Press TV