Iranian President Masoud Pezeshkian condemned Israel's air strikes on the Lebanese capital's densely populated southern suburbs Friday as a "flagrant war crime."
"The attacks perpetrated ... by the Zionist regime in the Dahiya neighbourhood of Beirut constitute a flagrant war crime that has revealed once again the nature of this regime's state terrorism," Pezeshkian said in a statement carried by the official IRNA news agency early Saturday.
Israel said its strikes targeted the "central headquarters" of Lebanese militant group Hezbollah, an Iranian ally.
Pezeshkian vowed Iran "will stand with the Lebanese nation and the axis of resistance".
Friday's strikes were by far the fiercest to hit Beirut since Israel shifted its focus from the war in Gaza to Lebanon this week, pounding Hezbollah strongholds around the country and killing hundreds of people.
The Iranian embassy in Lebanon warned that they marked a "dangerous escalation" in the Middle East.
"This reprehensible crime... represents a dangerous escalation that changes the rules of the game," the embassy said in a post on X, adding that Israel "will receive the appropriate punishment".
The Iranian foreign ministry said that the "brutal" strike gave the lie to a US-led ceasefire call issued on the eve of the strike.
"The continuation of the Zionist regime's crimes shows clearly that the ceasefire call issued by the United States and some Western countries is a blatant trick aimed at winning time for the Zionist regime to continue its crimes against the Palestinian and Lebanese peoples," ministry spokesman Nasser Kanani said in a statement
Hezbollah started fighting Israeli troops along the Lebanon border a day after its Palestinian ally Hamas staged its unprecedented attack on Israel on October 7.