UN nuclear watchdog says it is increasingly concerned about an Iranian enrichment plant it has never inspected

A plant no one has seen

The International Atomic Energy Agency (IAEA) called on Iran to restore access for its inspectors in a report circulated to member states on Friday, saying this was essential for it to monitor the Iranian nuclear programme, Al Jazeera and the BBC reported. The agency said it was “increasingly concerned” about a uranium enrichment plant near Isfahan that it has not been allowed to inspect.

Iran told the IAEA about plans for the Isfahan Fuel Enrichment Plant on 12 June 2025, a day before Israel began attacking its nuclear sites; the United States joined the strikes later that month. An inspection was agreed but cancelled after the attacks began, the BBC said. According to the report, inspectors still do not know the plant’s exact location or whether it holds nuclear material, and the report did not establish that enrichment is taking place there.

“The Agency’s lack of information about [Iran’s] nuclear material and access to facilities to verify it is a matter of serious proliferation concern... and needs to be rectified with the utmost urgency.”

IAEA report, BBC News World

The missing uranium

Since the strikes the agency has been unable to verify the status of Iran’s stockpile of highly enriched uranium. Under the 2015 nuclear deal Iran agreed to limit its stockpile to 300kg and enrichment to 3.67% purity, but later exceeded both. Before the June 2025 strikes it had an estimated 441kg enriched to 60%, close to weapons grade, the BBC reported.

The Isfahan complex was badly damaged in the strikes, especially above ground, and the state of its underground facilities is unclear. The IAEA believes much of Iran’s highly enriched uranium was stored there. Almost a year ago the agency said it had inspected only some of the 13 Iranian nuclear facilities unaffected by the attacks and none of the seven that were hit.

Iran’s answer

Iran told the agency this month that talks on resuming inspections could not take place amid “persistent, explicit, and public threats by the President of the United States of America … to commit further acts of armed aggression”, according to the report cited by Al Jazeera. The IAEA withdrew its inspectors for safety reasons, and Iran later passed a law suspending cooperation with it.

The IAEA director general, Rafael Grossi, urged Iran to consider limited technical measures that would make visits possible, AFP reported. The agency said it was “fully prepared to resume its safeguards activities in Iran at short notice”. Iran’s foreign ministry spokesperson, Esmaeil Baghaei, said on Monday that Iran remained committed to the Non-Proliferation Treaty but blamed the US and Israeli attacks for limiting cooperation. Iran says its programme is purely civilian.