UN nuclear watchdog says it doesn't even know where Iran's underground Isfahan enrichment plant is, or what's inside it

The International Atomic Energy Agency, the UN nuclear watchdog, says it is "increasingly concerned" about an underground uranium-enrichment plant at Isfahan that Iran declared last year but has never let inspectors see, according to a confidential report sent to member states Friday and seen by Reuters.

"The Agency does not know IFEP's exact location, status for safeguards purposes, or whether it contains nuclear material," the IAEA said in its quarterly report on Iran, referring to the Isfahan Fuel Enrichment Plant.

Iran announced the Isfahan enrichment plant in June 2025, around the time of the US and Israeli strikes on its nuclear sites. According to the report, Iran has neither allowed inspections there nor provided design details for the facility.

The report comes ahead of next week's meeting of the IAEA Board of Governors in Vienna. Wire summaries of the report say the agency still lacks data on Iran's enriched uranium and access to its facilities since June 2025, and that IAEA chief Rafael Grossi says Iran is still unwilling to work with the agency to resolve the open safeguards problems.

The finding lands as the US and Iran remain at war and Tehran keeps threatening shipping in the Strait of Hormuz.