By all accounts, Hassan Nasrallah was killed in Israel's massive bombing raids against Hezbollah strongholds in Lebanon's capital Beirut during the night leading up to Saturday.
"Nasrallah will no longer be able to terrorize the world", Israel's military wrote on its official X account in the morning.
Hezbollah vows in its statement to continue the "holy war" against the enemy, but does not announce who will lead the movement forward, according to several media outlets.
A high-ranking general within the powerful Iranian Revolutionary Guard, Abbas Nilforoushan, was also killed in one of Israel's attacks in Lebanon in the past 24 hours, according to Iranian state media.
US President Joe Biden calls the killing "a measure of justice for his many victims, including thousands of Americans, Israelis, and Lebanese civilians".
In a statement, he reiterates the US's support for Israel's right to defend itself against Iran-backed terrorist groups, and says he has tasked Defense Minister Lloyd Austin with "further strengthening the defense positions of US military forces" in the region.
Iran's leader relocated
Lebanon has declared three days of national mourning.
In light of Nasrallah's death and the recent targeted bombing attacks on southern Beirut, Israel's army chief Herzi Halevi says that anyone who threatens the country and its citizens will be attacked.
The message is simple, to all who threaten the citizens of the State of Israel, we know how to get to you, he says according to AFP.
The statement appears to be heeded by Israel's antagonist Iran, which is very close to Hezbollah. The country's supreme leader Ayatollah Ali Khamenei has been moved to a "safe location" and the security apparatus around him has been strengthened, reports news agency Reuters, citing sources in Tehran.
According to the sources, Iran's leadership is in contact with Hezbollah and other groups in the region. Discussions are underway on how to respond after Israel's deadly attacks.
"Holding on" in the fight
Khamenei condemns in a statement what he calls "Israel's short-sighted policy" and "the massacre of the defenseless people of Lebanon", without mentioning the reports of Nasrallah's death. He urges all Muslims to unite to help the people of Lebanon and Hezbollah to "confront the occupying, cruel, and evil regime", according to CNN.
Israel says it still has "a bit left" in the fight against Hezbollah, says a military spokesperson, who adds that most of the important Hezbollah leaders have been eliminated.
Over 700 people have been killed in the recent Israeli attacks on Lebanon, and hundreds of thousands of people have been driven into flight, reports AFP.
Shia Muslim Hezbollah's goal is to eradicate Israel and create an Islamic state in Lebanon.
The organization has Iran's backing and is often referred to as "a state within a state" due to its strong military and political power in the country.
According to Hezbollah, its military forces consist of around 100,000 soldiers, a figure that Israel strongly questions.
A large part of the movement's military strength comes from Iranian support. Hezbollah engages in welfare activities but also has a military branch that carries out attacks on Israel and terrorist activities.
The movement as a whole has been labeled a terrorist organization by several countries, while others have chosen to only label its armed branch as such.
