The Israeli military said the targeted militant, Hassan Farhat, was behind a rocket attack on the city of Safed last year that killed and wounded several Israeli soldiers. It vowed to act against Hamas fighters “wherever they operate”.

A security source said Farhat was killed along with his son and daughter in the strike in the southern Lebanese city of Sidon. Hamas’ armed wing the al-Qassam Brigades said Farhat was assassinated in his apartment in Sidon, and praised his “blessed contributions” to the confrontation with Israel over the years.

Iran-backed Hezbollah condemned the strike in a statement, saying that the “targeting of Sidon is evidence of the enemy’s intention to expand the scope of its aggression and target all of Lebanon”.

Hamas and Hezbollah are allies, and Hezbollah launched a campaign of cross border strikes on Israel in solidarity with the Palestinian group in 2023. Israel responded with a major air and ground campaign in Lebanon last year that killed much of the Hezbollah leadership.

Lebanese Prime Minister Nawaf Salam’s office said Friday’s Israeli attack was a clear violation of a U.S.-backed ceasefire.

The ceasefire, agreed in November, has appeared increasingly precarious in recent weeks, with Israel striking the Hezbollah-controlled southern suburbs of Beirut twice and rockets being fired on two occasions from Lebanon towards Israel.

Hezbollah also accused the ceasefire sponsors, led by the U.S., of overlooking Israeli attacks.

The U.S. backed Israel after the Israeli strikes in Beirut’s southern suburbs and said Israel was defending itself, blaming “terrorists” for the resumption of hostilities.

Hezbollah has denied any role in the recent rocket fire.