Iran’s highly enriched uranium likely at Isfahan: UN nuclear chief

Iran’s Highly Enriched Uranium Likely Still at Isfahan Complex, Says IAEA Chief

The majority of Iran’s highly enriched uranium is likely still stored at its Isfahan nuclear complex, according to Rafael Grossi, the head of the International Atomic Energy Agency (IAEA). Speaking in an interview with The Associated Press on Tuesday, Grossi confirmed that the UN nuclear watchdog continues to receive information and satellite images showing the effects of recent U.S.-Israeli airstrikes against Iranian facilities.

IAEA inspections at Isfahan were halted last June when Israel launched a 12-day military campaign that ultimately saw the United States bomb three Iranian nuclear sites. Despite the suspension of physical inspections, the agency believes a significant portion of Iran’s nuclear material has remained at the facility.

“We haven’t been able to inspect or to reject that the material is there and that the IAEA seals remain there,” Grossi explained. “What I tell you is our best estimate.”

Satellite imagery from Airbus captured a truck loaded with 18 blue containers entering a tunnel at the Isfahan Nuclear Technology Center on June 9, 2025, just before last year’s conflict began. These containers, believed to hold highly enriched uranium, likely remain stored underground at the site.

The IAEA is also seeking to inspect Iran’s nuclear facilities at Natanz and Fordo, where additional nuclear material is stored. As a signatory to the Nuclear Nonproliferation Treaty, which is currently undergoing its five-year review at UN headquarters, Iran is obligated to permit IAEA inspections of its nuclear facilities.

According to agency assessments, Iran possesses approximately 440.9 kilograms (972 pounds) of uranium enriched up to 60% purity—just a technical step away from weapons-grade levels of 90%. Grossi has previously indicated that roughly 200 kilograms (440 pounds) of this material is stored in tunnels at the Isfahan complex.

Last year, Grossi warned that Iran’s current stockpile could potentially allow the country to construct as many as 10 nuclear bombs should it decide to weaponize its program. Iranian authorities have consistently maintained that their nuclear program serves peaceful purposes only.

President Donald Trump has cited preventing Iran from developing nuclear weapons as a primary motivation for U.S. military action, claiming that strikes last summer “obliterated” the country’s atomic program. However, Grossi revealed that a new uranium enrichment facility declared by Iran at Isfahan last June apparently escaped damage in both recent attacks.

The IAEA has engaged in discussions with Russia and other nations about potentially removing Iran’s highly enriched uranium from the country—a complex operation that would require either diplomatic agreement or significant military intervention. Trump confirmed on Wednesday that Russian President Vladimir Putin had renewed an offer to assist with handling Iran’s enriched uranium, though Trump indicated he prioritized Russia’s involvement in ending the Ukraine conflict.

“What’s going to be important is that that material leaves Iran” or is blended to reduce its enrichment level, Grossi emphasized.

The IAEA participated in U.S.-Iran nuclear negotiations in February but has not been involved in recent ceasefire talks mediated by Pakistan. The agency has maintained separate discussions with U.S. officials and informal communications with Iran.

Trump told Axios on Wednesday that he has rejected Iran’s latest proposal, which sought to postpone nuclear program discussions but offered to end its chokehold on the strategically crucial Strait of Hormuz if the U.S. lifted its blockade and ceased hostilities.

Grossi noted that the current situation differs dramatically from 2015, when Iran agreed to limit its nuclear program under a deal with major powers. Since Trump withdrew the U.S. from that agreement in 2018, Iran has made “exponential progress” in uranium enrichment technology, utilizing advanced centrifuges and developing new facilities.

Reaching a new agreement would require “political will” from Tehran, Grossi told AP. “Iran has to be convinced that it is important to negotiate.” While leaders from both Iran and the U.S. express willingness to negotiate, they remain at an impasse regarding sequencing and initial steps.

Secretary of State Marco Rubio expressed skepticism about Iran’s intentions, telling Fox News that Iranian negotiators are “skilled” at buying time and emphasized that any agreement must “definitively prevent them from sprinting towards a nuclear weapon at any point.”

Despite these challenges, Grossi, describing himself as a negotiator who looks for a “flicker of hope,” observed that both sides appear interested in eventually reaching an agreement.