VIENNA – June 23: The head of the United Nations nuclear watchdog has warned of likely “very significant” damage to Iran’s Fordow uranium enrichment site following recent U.S. airstrikes targeting key nuclear facilities.
Rafael Grossi, Director General of the International Atomic Energy Agency (IAEA), addressed the agency’s emergency Board of Governors meeting on Monday, saying the underground damage at Fordow cannot yet be fully assessed. However, he noted that the use of ground-penetrating munitions and the sensitivity of centrifuges indicate major destruction.
“At this time, no one, including the IAEA, is in a position to have fully assessed the underground damage at Fordow,” Grossi said.
“Given the explosive payload utilised and the extremely vibration-sensitive nature of centrifuges, very significant damage is expected to have occurred.”
The U.S. strikes, which took place early Sunday, involved the use of the largest conventional bunker-busting bombs in America’s arsenal. The Fordow facility, built deep inside a mountain, was among the primary targets. The attacks also hit other major Iranian nuclear sites, including Natanz and Isfahan.
Grossi reported visible craters at the Fordow site and confirmed that the fuel enrichment plant at Natanz and uranium conversion infrastructure at Isfahan were damaged. Tunnel entrances used to store enriched material at Isfahan were also struck.
“Craters are now visible at the Fordow site,” Grossi noted. “At the Esfahan nuclear site, additional buildings were hit… affected buildings include some related to the uranium conversion process.”
Iran informed the IAEA on June 13 that it would implement “special measures” to protect its safeguarded nuclear materials and equipment in light of escalating threats. Grossi responded that any such transfer of nuclear material must be declared to the agency, in accordance with Iran’s Safeguard Agreement.
“Any special measures by Iran to protect its nuclear materials and equipment … can be done in accordance with Iran’s safeguards obligations … This is possible.”
The IAEA has not been able to inspect the damaged facilities since hostilities escalated. Grossi called for an immediate halt to the military strikes and urged the resumption of diplomatic negotiations to prevent further deterioration of the global nuclear non-proliferation regime.
“Military escalation not only threatens lives, it also delays us from taking the diplomatic path,” he said.
“We must return to the negotiating table… We need to keep working together despite existing differences.”
Tehran has threatened to suspend its cooperation with the IAEA and has raised the possibility of withdrawing from the Nuclear Non-Proliferation Treaty (NPT). During the meeting, Grossi reiterated his readiness to travel to Iran immediately and called on Iranian authorities to allow inspectors access to assess the situation.
“Our inspectors remain in Iran ready to undertake the required tasks when agreed with Iran,” Grossi stated.
“We will not be safer if there are more nuclear weapons in more states around the world.”
No increase in radiation has been reported from any of the sites bombed. The IAEA continues to monitor the situation and is coordinating with Iranian authorities and international bodies to ensure safety and security.
IAEA Director General @RafaelMGrossi addressed the Board of Governors this morning at an emergency meeting regarding the situation in Iran. pic.twitter.com/lqVr07Sqg7
— IAEA – International Atomic Energy Agency ⚛️ (@iaeaorg) June 23, 2025