The UN's nuclear watchdog has said it is "increasingly concerned" about a nuclear facility in Iran which it has not been allowed to inspect.
Iran informed the International Atomic Energy Agency (IAEA) of plans to set up the uranium enrichment plant in the city of Isfahan a day before Israel began attacking its nuclear sites last June. The US joined the strikes later that month.
In a report seen by news agencies, the IAEA said it does not know the exact location or whether it contains nuclear material.
Since the start of the latest war, Iran has restricted IAEA inspectors' access to its nuclear sites, preventing the agency from verifying its enriched uranium stockpile.
Under a 2015 nuclear deal, Iran agreed to limit its enriched uranium stockpile to 300kg and enrichment to 3.67% purity. It subsequently exceeded both.
Before the June 2025 strikes, it had accumulated an estimated 441kg enriched to 60%, close to weapons grade.
The nuclear complex at Isfahan suffered extensive damage in US and Israeli strikes, particularly the parts above the ground. The condition of its underground facilities is not clear.
The IAEA believes much of Iran's highly enriched uranium was stored 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," it said in the latest report.
Iran announced plans for the Isfahan Fuel Enrichment Plant (IFEP) on 12 June 2025, shortly after an IAEA resolution which declared Iran had failed to meet its nuclear safeguards obligations.
Iran initially agreed to allow inspectors to visit the facility, but the inspection was cancelled after Israel launched attacks the following day.
The IAEA's latest calls come almost a year after it made a similar appeal to Iran. At the time it said it had only inspected some of the 13 nuclear facilities that were "unaffected" by the attacks and none of the seven that were.
The US and Israel said they attacked Iran's nuclear sites to prevent it developing nuclear weapons - something Iran has consistently denied seeking. It says its nuclear programme is for peaceful civilian purposes only.
