An Israeli airstrike on the southern Lebanese city of Sidon on Friday killed a senior Hamas commander, further straining an already fragile ceasefire between Israel and Hezbollah that ended last year’s hostilities.

The Israel Defense Forces (IDF) confirmed the death of Hassan Farhat, who it said was responsible for a 2023 rocket attack on the northern Israeli city of Safed that resulted in casualties. In a statement, the IDF pledged to continue targeting Hamas operatives “wherever they operate.”

According to a regional security source, Farhat’s son and daughter were also killed in the strike, which targeted the family’s apartment. Hamas’ armed wing, the al-Qassam Brigades, accused Israel of carrying out an assassination and praised Farhat’s longstanding role in its military campaign.

The strike drew strong condemnation from Hezbollah, which called it a clear sign of Israel’s intent to widen its military operations across Lebanon. “The targeting of Sidon is evidence of the enemy’s intention to expand the scope of its aggression and target all of Lebanon,” Hezbollah said in a statement.

Hezbollah and Hamas, both backed by Iran, maintain a military alliance. During the 2023 conflict between Israel and Hamas, Hezbollah launched cross-border attacks in support of Hamas, prompting a large-scale Israeli counteroffensive that severely impacted Hezbollah’s leadership in Lebanon.

Lebanese Prime Minister Nawaf Salam’s office denounced Friday’s strike as a direct violation of the U.S.-brokered ceasefire agreement reached in November. The truce has shown increasing signs of unraveling in recent weeks, with Israeli airstrikes hitting Hezbollah strongholds in Beirut’s southern suburbs and continued rocket fire from Lebanon into northern Israel.

The latest developments have raised fears of a broader regional escalation as tensions simmer on both sides of the Israeli-Lebanese border.