America News Agency

On Saturday, Ayatollah Ali Khamenei declared five days of official mourning and called an emergency meeting of the 57-member Organization of Islamic Cooperation as shock waves from Friday night's airstrike that killed Nasrallah reverberated across the region and Israel continued to strike targets in Lebanon. Iran also called a meeting of the UN Security Council over Israel's actions in Lebanon and across the region.

Israeli security forces have also been put on alert for possible retaliation. At the same time, experts have warned that the region faces several scenarios following the killing, including the risk of a widening war that could draw Iran, Hezbollah's main backer, into a confrontation with Israel.

Israeli Prime Minister Benjamin Netanyahu said on Saturday that Nasrallah's killing was a historic turning point that could change the balance of power in the Middle East, but warned of “difficult days” ahead.

“Nasrallah was not a terrorist; he was a terrorist,” Netanyahu said in a statement.

“The killing of Nasrallah was a necessary step to achieve the goals we set, to return the residents of the north safely to their homes and to change the balance of power in the region in the coming years.”

US President Joe Biden called Nasrallah's killing “a measure of justice for his many victims, including thousands of American, Israeli and Lebanese civilians” and ordered the Pentagon to strengthen America's defence posture in the region. Biden added that the United States “fully supports Israel's right to defend itself against Hezbollah, Hamas, the Houthis and other Iranian-backed terrorist groups.”

Other world leaders, however, expressed concern over Nasrallah's assassination. UN Secretary-General António Guterres joined other leaders in warning of the danger of destabilization, saying he was “gravely concerned” by the “dramatic escalation” in Lebanon.

Nasrallah, who led Hezbollah for more than three decades, was killed in a series of Israeli attacks on the group's underground headquarters in Dahieh, a southern suburb of Beirut.