"The defeat of the Zionist regime in Gaza will continue and this regime will be close to decline and dissolution," Khamenei said in a speech to the country's officials in Tehran.

"Desperate efforts like the one they committed in Syria will not save them from defeat. Of course, they will also be slapped for that action," he added.

Iranian state media said 13 people were killed in the strike in which, according to Tehran's ambassador, Israeli F-35 jets fired six missiles that levelled the five-storey consular building adjacent to the embassy.

Iran said the strike killed seven Islamic Revolutionary Guard Corps members, including two commanders of the Quds Force -- the Guards' foreign operations arm -- Brigadier Generals Mohammad Reza Zahedi and Mohammad Hadi Haji Rahimi.

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

Iran's official media said the funeral ceremony of the IRGC members would be held on Friday, coinciding with the annual Quds Day, which will see Iranian people march in support of Palestinians and against Israel.

Iran's supreme leader, who has the final say in major state policies, urged people to take to the streets for this year's event.

"If in previous years, Quds Day was celebrated only in Islamic countries, this year, most likely, Quds Day will also be celebrated in non-Islamic countries."

He also said he hoped for a day that "the Muslim world can celebrate the destruction of Israel."

Israel has long fought a shadow war of assassinations and sabotage against Iran and its armed allies, including Lebanon's Hezbollah and other militant groups.

Regional tensions have soared since the Gaza war erupted with Hamas's October 7 attack that resulted in about 1,160 deaths in Israel, mostly civilians, according to an AFP tally of Israeli official figures.

The Palestinian militant group is backed by Tehran, although Iran has denied any direct involvement in the attack.

Israel's retaliatory offensive against Hamas has killed at least 32,975 people in Gaza, mostly women and children, according to the Hamas-run territory's health ministry.