“The evil Zionist regime will be punished at the hands of our brave men. We will make them regret this crime and the other ones,” Khamenei said in a message published on his official website.

President Ebrahim Raisi condemned the attack as a “clear violation of international regulations” which “will not go unanswered”.

“After repeated defeats and failures against the faith and will of the Resistance Front fighters, the Zionist regime has put blind assassinations on its agenda in the struggle to save itself,” Raisi said on his office’s website.

The UN Security Council is to discuss the strike later on Tuesday at a meeting requested by Syrian ally Russia.

The strike on the annex killed seven Revolutionary Guards, including two commanders of its Quds Force foreign operations arm, Brigadier Generals Mohammad Reza Zahedi and Mohammad Hadi Haji Rahimi, Iranian officials said.

Zahedi, 63, had held a succession of commands in the force in a Guards career spanning more than four decades.

Iran vows revenge as Israel strike in Syria kills 5 Revolutionary Guards

A Britain-based monitor of the more than decade-old conflict in Syria, the Syrian Observatory for Human Rights, said the strike killed “eight Iranians, two Syrians and one Lebanese – all of them fighters.”

Iran’s ambassador to Syria, Hossein Akbari, told Iranian state TV that the attack “was carried out by F-35 fighter jets” which fired six missiles at the building.

Only the gate of the building was left standing after the attack, with a sign reading “the consular section of the embassy of Iran”.

Windows were shattered within a 500-metre (550 yard) radius, and many parked cars were damaged by the blast.

The adjacent facade of the Iranian embassy is decorated with a large portrait of Qassem Soleimani, a long-time Quds Force chief who was killed in a US drone strike just outside Baghdad airport in January 2020.

Iran’s foreign minister said Israel’s main backer the United States also bore responsibility for the strike, even though an unidentified US official quoted by Axios insisted Washington “had no involvement” or advanced knowledge of it.

Amir-Abdollahian said on X that the ministry had summoned a diplomat from the Swiss embassy, which looks after US interests in Iran, to hear its protest.

“An important message was sent to the American government as the supporter of the Zionist regime. America must be held accountable,” he said in the post.

Iran’s mission to the United Nations warned the strike could “potentially ignite more conflict involving other nations” and called on the Security Council “to condemn this unjustified criminal act.”

Iran’s allies around the region and beyond voiced support for its position.

“China condemns the attack,” foreign ministry spokesperson Wang Wenbin said, adding “the security of diplomatic institutions cannot be violated, and Syria’s sovereignty, independence and territorial integrity should be respected”.

The Iraqi foreign ministry condemned the attack as a “flagrant violation of international law” and warned of “more chaos and instability” in the region.

Lebanon’s Iran-backed Hezbollah group warned Israel would pay for killing Guards commanders. “This crime will not pass without the enemy receiving punishment and revenge,” Hezbollah said in a statement.

Russia blamed the Israeli air force for the “unacceptable attack against the Iranian consular mission in Syria”.

Palestinian militant group Hamas condemned the strike, which it described as a “dangerous escalation”.

The Gaza war erupted with Hamas’s unprecedented October 7 attack that resulted in about 1,160 deaths in Israel, mostly civilians, according to Israeli official figures.

Israel’s retaliatory offensive against Hamas has killed nearly 33,000 people in Gaza, mostly women and children, according to the Hamas-run territory’s health ministry.

Iran-backed groups in Iraq, Lebanon, Syria, and Yemen have since carried out a series of attacks on Israeli and Western targets.