Iran into Monday had so far held off retaliating against the United States for its surprise attack by submarine missiles and heavy bombers the previous day, as Supreme Leader Ali Khamenei saved his threats for Israel.
"The punishment continues," a post on the 86-year old leader's X account wrote.
"The Zionist enemy has made a grave mistake, committed a major crime; it must be punished—and it is being punished. It is being punished right now. #AllahuAkbar".
No mention was made of the United States in his remarks, the first since US President Donald Trump proudly declared his forces had bombed three nuclear sites.
His post came as Israeli military authorities said only a single missile was fired at it by Iran in an attack overnight, in a possible sign of depleted power.
The day after the attack, the hawkish president upped the ante yet again, suggesting regime change would be welcome if Tehran could not "Make Iran Great Again".
"It’s not politically correct to use the term, 'Regime Change,' but if the current Iranian Regime is unable to MAKE IRAN GREAT AGAIN, why wouldn’t there be a Regime change??? MIGA!!!" Trump wrote.
Protests
Protests were held on Sunday in far-flung cities against the US attack on Iran's nuclear sites, including in Los Angeles, Karachi and outside a NATO meeting at The Hague.
Russia's United Nations ambassador Vassily Nebenzia hit out a what he called a rerun of the US Iraq War, based on weapons of mass destruction which were never found.
"Again we're being asked to believe the US's fairy tales, to once again inflict suffering on millions of people living in the Middle East," Nebenzia said.
US President Donald signaled he would accept little opposition as he tore into a lawmaker critic from his own Republican party on social media.
Kentucky congressman Thomas Massie had called out Trump, saying on X:"This is not America First folks.
What war wrought
Israel's attacks on Iran have so far killed 950 people and injured 3,450, human rights group HRANA reported on Sunday.
Meanwhile no clear picture had yet emerged on the impact of US attacks and whether it achieved its goal of ending Iran's nuclear ambitions.
The UN nuclear watchdog said Sunday that entrances to underground tunnels at Iran’s Isfahan nuclear complex were damaged in the strikes.
“We have established that entrances to underground tunnels at the site were impacted,” the International Atomic Energy Agency (IAEA) said in a statement.
The IAEA chief Rafael Grossi told CNN it was too early to assess the underground damage to Iran's Fordow site.
Iranian defiance
Iran's foreign minister arrived in Moscow for talks with Russian President Vladimir Putin after appearing to vow Iranian retaliation in Turkey.
"The US crossed a very big red line by attacking Iran’s nuclear facilities," Abbas Araghchi said. Speaking in Istanbul, Araghchi said the US bore full responsibility.
“The attack on peaceful nuclear installations marks a dangerous precedent and will not go unanswered."
Relative moderate President Masoud Pezeshkian also promised a rejoinder.
“The US has attacked us. What would you do if you were in our position? Naturally, they must receive a response to their aggression,” Pezeshkian said.
Veteran security insider Ali Shamkhani said the strikes would not sink Iran's nuclear enterprise.
“Even if nuclear sites are destroyed, the game isn’t over... enriched materials, indigenous knowledge, and political will remain,” Shamkhani said on X.
“The initiative is now with the side that plays smart, avoids blind strikes. Surprises will continue!”
