The head of the UN’s nuclear watchdog has said centrifuges at Iran’s underground uranium enrichment facility at Natanz were “severely damaged if not destroyed altogether” following Israeli airstrikes last Friday. Rafael Grossi, Director General of the International Atomic Energy Agency (IAEA), told the BBC that the damage was likely caused by power cuts triggered during the attack, which also “completely destroyed” the plant’s above-ground infrastructure.
While the underground cascade hall housing the enrichment machines was not directly hit, Grossi warned that the sudden loss of external power may have caused cascading internal failures. “Our assessment is that with this sudden loss of external power, in great probability the centrifuges have been severely damaged if not destroyed altogether,” he said.
Centrifuges—high-precision machines used to enrich uranium—are extremely sensitive to operational disturbances. A disruption such as a power cut can destabilize them, potentially destroying entire cascades of machines in seconds.
Grossi confirmed that while there was some radiological and chemical contamination within the site, radiation levels outside Natanz remained at normal, safe levels.
In addition to Natanz, Israel also struck Iran’s Isfahan Nuclear Technology Centre, destroying four key buildings, including a central chemical lab, a uranium conversion plant, and a facility under construction to produce uranium metal. According to Grossi, underground spaces at Isfahan do not appear to have been affected. Israel claims the attack dismantled critical infrastructure used in uranium processing and conversion.
No visible damage was reported at the Fordo underground enrichment site or the Khondab heavy water reactor currently under construction, Grossi said. However, Iranian media claimed there was “limited damage” at Fordo. Israel has not confirmed any operations there.
The Israeli military stated that the strikes aimed to prevent Iran from advancing its alleged nuclear weapons program, claiming it had killed nine Iranian nuclear scientists in the process. Iran maintains that its nuclear activities are strictly for peaceful purposes and condemned the Israeli strikes as violations of international law.
In response, Iran launched missile attacks on Israel, with its foreign minister declaring the strikes a “response to aggression.” Iranian authorities report over 220 deaths from Israeli airstrikes since Friday, while Israeli officials say 24 of their citizens were killed by Iranian missiles.
The escalating confrontation comes amid renewed scrutiny of Iran’s nuclear ambitions. Just days before the attacks, the IAEA’s board of governors declared Iran in formal breach of its nuclear non-proliferation obligations for the first time in two decades, citing continued failure to provide answers regarding undeclared nuclear materials and activities.
Since the U.S. withdrew from the 2015 nuclear deal in 2018 under former President Donald Trump, Iran has gradually ramped up its uranium enrichment, reaching 60% purity—just below the threshold required for nuclear weapons. The IAEA has assessed that Iran now possesses enough enriched material to potentially construct nine nuclear warheads.
Grossi has urged all parties to de-escalate, warning that further military action could pose significant risks to both human life and the environment. “Military escalation increases the chance of a radiological release with serious consequences,” he cautioned.