The Israeli military says it has confirmed that an airstrike about three weeks ago killed a possible successor to the late leader of the Lebanon-based Shia Muslim group Hezbollah.

Israel said on Tuesday that the strike in the suburb of the Lebanese capital Beirut killed senior Hezbollah official Hashem Safieddine. He had been widely expected to replace Hassan Nasrallah, the group's former leader who was killed last month in Israeli airstrikes.

The Israeli military is continuing air attacks on targets related to Hezbollah. It announced on Wednesday that it conducted intelligence-based strikes on several weapons storage and manufacturing facilities, as well as command centers belonging to the group.

Health authorities in Lebanon say 2,546 people have been killed since the start of the Israeli offensive last October.

The US government is calling on the two sides to work toward a diplomatic settlement to prevent further escalation.

US news site Axios reports that Israel demands as conditions for a diplomatic solution that its military be allowed "active enforcement" in areas of southern Lebanon and freedom to operate in Lebanese air space.

But the outlet cited a US official as saying it is highly unlikely that Lebanon will agree to the conditions, which would conflict with a previous UN Security Council resolution.