The Israeli military said Hassan Nasrallah, who led Hezbollah for 32 years, was killed in an air strike on the southern suburbs of Beirut, the Iran-backed group’s main bastion, on Friday. Hezbollah confirmed his death on Saturday.
The Israeli military called Nasrallah, 64, "one of the greatest enemies of the State of Israel of all time" and said that "his elimination makes the world a safer place."
Iran’s Supreme Leader Ayatollah Ali Khamenei said killing Hezbollah commanders would not bring the group to its knees and declared public mourning.
Iran also called for the UNSC to meet over Israeli actions and warned against any attacks on its diplomatic facilities and representatives.
"Iran will not hesitate to exercise its inherent rights under international law to take every measure in defense of its vital national and security interests," Iran's UN ambassador Amir Saeid Iravani wrote in a letter to the 15-member UNSC body.
Israeli Prime Minister Benjamin Netanyahu said Israel had “settled the score” for the killing of Israelis and citizens of other countries, including Americans.
Netanyahu said that as long as Nasrallah was alive, he could have "quickly restored the capabilities we had eroded from Hezbollah" in a series of recent operations.
US President Joe Biden — whose government is Israel’s top arms supplier — said it was a “measure of justice”.
More than 1,000 people have been killed in Israeli attacks on Lebanon in the past two weeks.
Israel and Hezbollah began fighting across the Lebanese border after the war in Gaza erupted when Hamas, a Hezbollah ally also backed by Iran, attacked Israeli towns on October 7 last year.