Hezbollah Secretary-General Naim Qassem has vowed to confront Israel "to the fullest extent", saying his group will defend itself regardless of the cost.
In a televised speech, Qassem described Hezbollah missile launches at Israel as "a response to 15 months of Israeli violations, including the killing of Khamenei."
"Our choice is to confront the enemy to the fullest extent, and we will not surrender," he said.
Qassem said Israeli attacks over the past 15 months had killed 500 people.
"As long as the occupation exists, resistance and its weapons are a legitimate right," he added.
Tensions escalate
Tensions have escalated in Lebanon after Hezbollah targeted a military site in northern Israel on Monday using rockets and drones.
The attack came in response to ongoing Israeli air strikes and the killing of Khamenei, according to Hezbollah.
Israel's military carried out a series of air strikes, killing at least 72 people and injuring nearly 450 others.
The Israeli army also launched a ground incursion into southern Lebanon.
Israel has repeatedly violated a ceasefire agreement signed with Hezbollah in November 2024, carrying out near-daily strikes that have left hundreds dead and wounded.
Meanwhile, the United States and Israel have continued large-scale attacks on Iran since Saturday.
The attacks have killed nearly 900 people, including Supreme Leader Ali Khamenei and senior military officials, according to reports.
