The Iran-backed Kataib Hezbollah said that Abu Haidar al-Khafaji was killed in a “Zionist assault” at dawn in Damascus. Khafaji had been working as a security advisor in the area, the group said in a statement on Telegram.

Iran's U.N. envoy warned the country had the "right to take all necessary measures to respond to this egregious violation."

Lebanon and Hezbollah have blamed Israel for the attacks on Tuesday and Wednesday that killed 37 people and wounded around 3,000, although Israel has not directly commented on the attacks, which security sources say were probably carried out by its Mossad spy agency.

Israel killed a senior Hezbollah commander and other leaders in a strike on southern Beirut Friday. It comes after deadly pager and walkie-talkie attacks this week. Follow for live news updates.

The attack represents another security failure for the militant group that has been reeling from repeated Israeli blows.

Amid fears of an expanding war in the Middle East following mass detonations of bombs surreptitiously planted in Hezbollah communication devices, Israel continued its assault of the Iran-backed militia overnight.

Israel’s operation against Hezbollah members in Lebanon and Syria through booby-trapped pagers and walkie-talkies was years in the making, and its use now ramped up a high-risk campaign aimed at deeply disrupting the group.