International Atomic Energy Agency chief Raphael Grossi fears an attack on nuclear facilities in Iran could lead to a radiological release, but says there is no evidence any of them have been hit so far.
The IAEA director general's comments came after Iran's ambassador to the agency said that the Natanz enrichment complex was hit on Sunday after the US and Israel began its bombing campaign.
“Again they attacked Iran's peaceful, safeguarded nuclear facilities yesterday,” said Reza Najafi as the emergency IAEA meeting opened in Vienna.
However, Mr Grossi said there has been no evidence of damage to any nuclear installations since the US and Israeli attacks began on Saturday. He said he hoped Iran would maintain lines of communication with his inspection operation.
“The situation is very concerning,” he warned. “We cannot rule out a possible radiological release with serious consequences, including the necessity to evacuate areas as large or larger than major cities.”
Mr Grossi said no elevation of radiation levels above usual background levels had been detected in countries bordering Iran.
From within Iran, the IAEA has “no indication” that any nuclear installations, including the Bushehr Nuclear Power Plant, the Tehran Research Reactor, or other fuel cycle facilities, have been hit or damaged.
Tehran and Washington were negotiating over the country's nuclear programme when the US and Israel began their latest bombing campaign on Saturday.
Iran's delegation in Vienna pointed out that the US strikes had killed Supreme Leader Ali Khamenei, who had issued an injunction against developing nuclear weapons.
“Under the false narrative of preventing Iran from developing nuclear weapons, the US committed the crime of aggression and martyred our Supreme Leader – the only Muslim scholar in contemporary history that issued a fatwa categorically prohibiting WMDs including nuclear weapons,” said Mr Najafi.
Iran suspended co-operation with the IAEA after the 12-day war with Israel last summer. Tehran criticised the watchdog for failing to condemn the strikes and said a resolution from the Vienna-based body had greenlighted the Israeli action.
Iran's parliament suspended all co-operation with the IAEA after the air war with Israel and the US last year. After bombing nuclear sites at Fordow, Isfahan and Natanz, US President Donald Trump said they were all “obliterated”.
Mr Grossi said after last summer's attacks that inspections were vital for international confidence.
For the first time since co-operation was suspended, the IAEA visited Tehran in August to hold talks with authorities about a new agreement. Iran and the IAEA then signed an agreement in September to restart inspections of Iran’s nuclear sites.
