Where did another enrichment site in Iran come from?

Avner Vilan, an expert on Iran's nuclear program who held senior positions in Israel's defense establishment, warns that an International Atomic Energy Agency (IAEA) report raises troubling questions about the scope of Iran's nuclear program and the ability of Israel and the United States to monitor its activities following strikes on its nuclear facilities. Vilan addressed information about an additional enrichment site in Isfahan in a recent tweet, whose existence Iran reported to the IAEA on June 12, 2025, just one day before the start of Operation Rising Lion.

He said agency inspectors had not had time to visit the site or verify its precise location, and its condition at the time and whether it held nuclear material remain unclear. Vilan acknowledged that the information had surprised him as well. He wrote, "I remembered that Iran had only two enrichment site, those at Natanz and Fordow. So where did an enrichment site in Isfahan suddenly come from?" He explained that the Atomic Energy Organization of Iran has operated a large complex in Isfahan for years, primarily used for uranium conversion and also containing a small research reactor.

He said tunnels at the complex were bombed during the US strikes in Operation Midnight Hammer in June 2025, but he had initially believed this was an enriched uranium storage site rather than an additional enrichment facility. He wrote, "But now, after reading the IAEA report and digging a little further online, I discovered to my surprise that this was a third enrichment site, which Iran reported to the IAEA on June 12, 2025, literally one day before the strike."

According to Vilan, this information means Iran has four sites with the potential for enrichment activity: Natanz, Fordow near Qom, Isfahan and another site known as "Pickaxe Mountain", where he said work had accelerated after Operation Rising Lion. Vilan criticized how the information had been presented to the public. He wrote, "I don't know why, but Israel, the US and the media downplayed this information about the additional enrichment site.

In every reference I can remember, they spoke about 'striking the tunnels in Isfahan,' or even 'striking the tunnel entrances.' No one talked about an enrichment site!." One of the main questions Vilan raises concerns the possibility that enriched nuclear material remained at the complex after the strikes. He stresses that, unlike the underground facility at Fordow, the Isfahan site is a sprawling industrial complex with numerous buildings and entrances, potentially making it harder to monitor activity there.

He warned, "If there really was an enrichment site there, and perhaps also fissile material (possibly some of the material enriched to 60%), then the assumption that the Iranians would not have known how to dig and reach the material over the past year and a half sounds even more dangerous to me." Vilan assessed that Iran could have used the complex's size to conceal activity involving nuclear materials and centrifuges. He expressed doubt about the ability to monitor everything happening at the site through aerial surveillance alone.

He wrote, "I assume I'm not telling the people whose job this is much they don't already know. There was a reason they sent the American bombs there. But allow me to be skeptical about our ability to monitor all the activity from the air." Despite the gravity of his remarks, Vilan clarified that the information did not fundamentally change the overall picture. Rather, he described it as a reminder of the limits of military achievements against Iran's nuclear program.

He argued, "This is not a game-changer, but a painful reminder that after two rounds of war, talk and declarations that 'we have set them back for generations' or similar nonsense, Iran is still dangerously close to the capability to develop nuclear weapons, and it has every motivation and interest in doing so." In his closing remarks, he called for a reassessment of the strategic objectives of another strike on Iran and its ability to produce a different outcome from what has been achieved so far.

He wrote, "Before we try to do more of the same and embark on another round of confrontation, which will exact a heavy toll on Iran but also on countries in the region, on Israel and on its international standing, perhaps this time we should ask ourselves what the objective of this round is and what will be different afterward. If the regime does not fall and the uranium remains in Iran, then what are we trying to achieve, and how does the chosen course of action move us toward that goal?"