"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.

"Day by day, we have witnessed the strengthening of the Resistance Front and the disgust and hatred of free nations towards the illegitimate nature of (Israel). This cowardly crime will not go unanswered."

The air strike on the Iranian embassy's five-storey annex killed seven members of the Islamic Revolution Guards Corps, which runs Iran's overseas military operations.

Among the dead, were Brigadier Generals Mohammad Reza Zahedi and Mohammad Hadi Haji Rahimi, both senior commanders in the Quds Force, Guards' foreign operations arm.

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

Israel declined to comment on the strike.

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

"Iran reserves its legitimate and inherent right under international law and the United Nations Charter to take a decisive response to such reprehensible acts," Iran's mission to the world body said.

It warned the strike could "potentially ignite more conflict involving other nations" and called on the Security Council "to condemn this unjustified criminal act."