Hezbollah said one of its top commanders was killed in an Israeli airstrike in southern Lebanon.
Mohammad Nima Nasser is the latest senior member of the Iran-backed Lebanese armed group to be targeted by Israel in nearly nine months of cross-border violence that has raised fears of an all-out war.
Hezbollah said it had fired 100 rockets and missiles at Israeli military positions “as part of its response to the assassination.” No injuries were reported.
The Israeli military said Nasser commanded a unit responsible for launching rockets from southwestern Lebanon and accused him of directing “a large number of terrorist attacks”.
It also described him as a “rival” to Taleb Sami Abdullah, the commander of another unit who was assassinated last month. Abdullah’s killing prompted Hezbollah to fire more than 200 rockets and missiles into northern Israel in one day.
Since then there has been a series of diplomatic efforts to ease tensions, with the United Nations and the United States warning that a war could have catastrophic consequences and could also draw Iran and other allies into it.
Since the war between Israel and Hamas broke out in Gaza on October 7, there have been almost daily exchanges of fire on the border between Israel and Lebanon.
Hezbollah said it was taking action to support the Palestinian group, which is also backed by Iran. Both are listed as terrorist organizations by Israel, the United Kingdom and other countries.
So far, more than 400 people have been reported dead in Lebanon, the vast majority of them Hezbollah fighters, and 25 people have been killed in Israel, mostly soldiers.
Tens of thousands of people in communities on both sides of the border have also been displaced.