The Iranian general who replaced the leader killed by a US airstrike in Baghdad has vowed to take revenge as Tehran abandoned the remaining limits of its 2015 nuclear deal with world powers in response to the slaying.
Esmail Ghaani's threat comes as the blowback over the US killing of top Iranian general Qassem Soleimani mounted with Iraq's parliament calling for the expulsion of all American troops from Iraqi soil.
The three developments could bring Iran closer to building an atomic bomb, see a proxy or military attack launched by Tehran against America and enable the Islamic State group to stage a comeback in Iraq, making the Middle East a far more dangerous and unstable place.
General Ghaani made his remarks in an interview with Iranian state television aired Monday.
"God the almighty has promised to get his revenge, and God is the main avenger. Certainly actions will be taken," General Ghaani said.
General Ghaani now serves as the head of the Revolutionary Guard's Quds Force, an expeditionary arm of the paramilitary organisation answerable only to Iran's Supreme Leader Ayatollah Ali Khamenei.
As Soleimani's longtime deputy, General Ghaani has been sanctioned by the US since 2012 for his work funding its operations around the world, including its work with proxies in Iraq, Lebanon and Yemen.
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Already, the US Embassy in Saudi Arabia warned Americans "of the heightened risk of missile and drone attacks."
In Lebanon, the leader of the Iranian-backed militant group Hezbollah said Soleimani's killing made US military bases, warships and service members across the region fair game for attacks. A former Iranian Revolutionary Guard leader suggested the Israeli city of Haifa and others could be targeted should the US attack Iran.
"We promise to continue down martyr Soleimani's path as firmly as before with help of God, and in return for his martyrdom we aim to get rid of America from the region," General Ghaani said.
Soleimani's killing has escalated the crisis between Tehran and Washington after months of back-and-forth attacks and threats that have put the wider Middle East on edge.
Iran has promised "harsh revenge" for the US attack, while Mr Trump has vowed on Twitter that the US will strike back at 52 targets "VERY FAST AND VERY HARD. "
He doubled down on that threat Sunday, dismissing warnings that targeting cultural sites could be a war crime under international law.
On Sunday, hundreds of thousands of mourners accompanied the coffin carrying Soleimani's remains in the Iranian cities of Ahvaz and Mashhad.
A similar procession was expected in Qom and Tehran on Monday. Tens of thousands already filled the streets of the Iranian capital early Monday morning.
Mourners wearing black beat their chests and carried posters with Soleimani's portrait. Demonstrators also unfurled red Shiite flags, which traditionally symbolise both the spilled blood of someone unjustly killed and a call for vengeance.
The processions mark the first time Iran honoured a single man with a multi-city ceremony. Not even Ayatollah Ruhollah Khomeini, who founded the Islamic Republic, received such a processional with his death in 1989.
Soleimani on Monday will lie in state at Tehran's famed Musalla mosque. He will be buried in his hometown of Kerman.