The Israeli military said on Friday it had killed Hassan Farhat, a commander of Palestinian group Hamas, in the Sidon region of southern Lebanon.
The Lebanese Health Ministry said three people were killed in an Israeli strike on an apartment in Sidon. Lebanese Prime Minister Nawaf Salam's office said the attack was a clear violation of a US-backed ceasefire which ended last year's war between Israel and the Iran-backed Hezbollah group.
The ceasefire 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 has denied any role in the rocket fire.
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