The UN nuclear watchdog's board of governors has voted to refer Iran to the UN Security Council over breaches of its non-proliferation obligations, diplomats said on Wednesday, marking the first such referral in 20 years.
The 35-member International Atomic Energy Agency board's resolution follows a finding adopted on June 12 last year that Tehran was in ‘non-compliance’ with its nuclear commitments.
The vote came a day before Israel launched strikes on Iranian nuclear facilities, with the United States later joining the attacks.
A separate resolution was required to formally report Iran's breach to the Security Council.
The referral is unlikely to lead to immediate concrete action against Tehran because Russia and China, both close Iranian allies, are permanent members of the council and can veto any substantive measure.
But the move nevertheless marks a significant escalation in the long-running diplomatic confrontation between Iran and Western powers.
Iran warned on Monday it would retaliate if the resolution passed.
An initial reaction by Iran's mission to the International Atomic Energy Agency, however, did not mention retaliation.
"Once again, a political resolution on Iran is nonconsensually adopted by the #IAEA BoG (Board of Governors)," it said on X, referring to the fact that the resolution was voted on rather than adopted without any country objecting.
"The current situation is created solely because of the criminal acts of aggression by the US and Israeli regime. The delusional objective of the US to force the great Iranian nation into 'surrender' and to plunder its oil will never happen," it added.
The resolution text, proposed by the US, Britain, France and Germany, passed with 23 votes in favour, three against and eight abstentions, said diplomats at the closed-door meeting, adding that those that opposed it were Russia, China and Niger.
"(The board) requests the (IAEA) Director General to report this resolution and the previously adopted resolutions ... to all Members of the Agency and to the Security Council and the General Assembly of the United Nations, in accordance with the relevant provisions of the IAEA Statute," the text read.
While the finding of non-compliance predates the war between the United States and Iran and concerns Tehran's failure to explain uranium traces found at undeclared sites that the agency spent years investigating, there is now another standoff over IAEA access to the sites bombed by Israel and the US.
Iran has not let IAEA inspectors return to its bombed sites, including the three uranium-enrichment plants at the heart of its nuclear programme that were destroyed or badly damaged in the military strikes.
Tehran has also not accounted for its stock of enriched uranium, some of which was enriched to up to 60% purity, a short step from the roughly 90% of weapons-grade.
"The Agency's lack of information about these facilities and associated nuclear material and our inability to conduct verification activities at these facilities is a matter of serious proliferation concern," IAEA chief Rafael Grossi told his agency's board on Monday.
"The situation needs to be rectified with the utmost urgency," he added.
The IAEA estimates Iran had 440.9 kg of uranium enriched to up to 60% before the US-Israeli attacks. That is enough, if enriched further, for 10 nuclear weapons, according to an IAEA yardstick. How much has survived is unclear, although the IAEA has said it believes more than 200 kg remains at one site.
Wednesday's resolution specifically mentioned two previous ones: the June 12, 2025 text finding Iran in non-compliance and the most recent one, from June of this year, telling Iran to declare its remaining enriched uranium stocks and let inspectors verify them.
