IAEA Warns It Does Not Know Where Iran’s Isfahan Enrichment Plant Is as Nuclear Monitoring Stalls

admin · November 13, 2026 · 8 min read

IAEA Director General Rafael Grossi briefs the press on his Iran visit in Vienna

The United Nations nuclear watchdog told its member states on Friday that it does not know where one of Iran’s declared uranium enrichment plants is, whether it is operating, or whether it contains nuclear material — the starkest admission yet of how little international inspectors can now see inside Iran’s nuclear program.

The International Atomic Energy Agency (IAEA) said in a confidential quarterly report circulated in Vienna on November 13 that it is “increasingly concerned” about the Isfahan Fuel Enrichment Plant, known as IFEP, an underground facility Iran declared in June 2025 but has never allowed inspectors to visit. Iran, meanwhile, told the agency this month that discussions on resuming nuclear monitoring cannot proceed while it faces what it called persistent threats of new military strikes by the United States.

What the IAEA report says

The report’s central warning concerns IFEP, a plant Iran formally declared to the agency on June 12, 2025 — one day before Israel launched a bombing campaign against Iranian nuclear facilities that the United States joined. The IAEA had planned to carry out an initial inspection of the plant on June 13, 2025, but the strikes began that day, making the visit impossible. No inspector has entered the site since.

“The Agency does not know IFEP’s exact location, status for safeguards purposes or whether it contains nuclear material,” the report said, according to Reuters, which reviewed the document. It added that the agency is “increasingly concerned” that Iran has not permitted it to inspect the plant or even to see its design information, which would show how the facility is configured and what it is built to do.

The plant is believed to be associated with a tunnel network at Isfahan, in central Iran. IAEA Director General Rafael Grossi said in March that the agency believed a significant quantity of Iran’s most highly enriched uranium was in the tunnel complex at Isfahan, Reuters reported.

The report also said Iran has not let inspectors return to any of the nuclear facilities bombed by Israel and the United States in the 12-day campaign in June 2025, and has not reported what happened to the uranium stored there. The only Iranian site inspectors have visited since June 2025 is the Bushehr power reactor, which they inspected from September 12 to 15, 2026.

Grossi wrote that it is “more than a year since the agency lost continuity of knowledge” of Iran’s declared stock of highly enriched uranium. The last verified figure dates from June 13, 2025: 440.9 kilograms of uranium enriched up to 60 percent purity — a short technical step from the 90 percent level considered weapons grade. Material of that kind should be checked by inspectors every month, the agency said.

The IAEA said it is “not able to conclude that there has been no diversion of declared nuclear material” in Iran, and described the lack of information about Iran’s nuclear facilities and material as a proliferation concern that “needs to be rectified with the utmost urgency.”

Iran says inspections must wait

Iran told the agency this month that talks on bringing inspectors back cannot go ahead amid “a series of persistent, explicit, and public threats by the President of the United States of America … to commit further acts of armed aggression” against Iran, “particularly targeting its nuclear facilities,” according to the report seen by the Associated Press.

Tehran said the situation would not be resolved “until the root causes of the present situation are addressed and the essential requirements for normal safeguards implementation are restored.” At the same time, Iran reaffirmed what it called its “firm commitment to resume full implementation of its safeguards obligations as soon as the relevant legal and actual conditions permit it.”

The report also said Iran raised concern in a letter to the agency about a recent U.S. offer of a reward of up to $20 million in exchange for information on Iran’s nuclear program.

The standoff comes a day after President Donald Trump said on social media that the United States does not need a deal with Iran. On Thursday, Trump also pulled Vice President JD Vance from efforts to engage Tehran in potential peace talks, saying Vance would instead focus on fraud investigations in Democratic-run jurisdictions. Trump has said in recent days that he could destroy Iran’s energy infrastructure, bridges and manufacturing within days if he chose to.

Grossi asked Iran to consider “technical and gradual measures” that would let inspectors return, and the agency said it is “fully prepared to resume its safeguards activities in Iran at short notice.”

Background: a monitoring system that stopped in June 2025

The IAEA’s safeguards system is the set of inspections, cameras, seals and measurements through which the agency verifies that nuclear material is not diverted from peaceful use. When inspectors cannot enter a facility, the agency cannot confirm what is inside it, whether any material is there, or whether material has been moved.

Before the June 2025 war, Iran’s declared stockpile of uranium enriched to 60 percent was the most sensitive part of its program. Grossi has previously warned that the stockpile could theoretically provide enough material for as many as 10 nuclear weapons if Iran decided to weaponize its program, the AP reported.

The June 2025 campaign destroyed or badly damaged Iran’s other uranium enrichment plants, the heart of its nuclear program, according to Reuters. The targets included the tunnel network at Isfahan where diplomats have said they believe IFEP is located, though a senior diplomat said its whereabouts and status remained unknown. The report is expected to be debated by the IAEA’s Board of Governors next week.

Why this matters

The report lands at a moment of acute tension between the United States, Israel and Iran. The U.S. military shot down two Iranian drones headed for Bahrain earlier this week, and Iran’s Revolutionary Guard claimed — without independent confirmation — that it destroyed a U.S. early-warning radar in Bahrain. The IAEA’s warning adds a nuclear dimension to a confrontation that has already produced threats of new strikes from Washington and retaliation threats from Tehran.

For the United States and its allies, the core concern is straightforward: roughly 441 kilograms of uranium enriched to 60 percent is unaccounted for in practical terms, and the agency charged with tracking it cannot say where it is. For Iran, the position is that it will not reopen its nuclear sites while the threat of another attack hangs over them.

The deadlock also complicates any return to diplomacy. Trump has said he does not need a deal, and Iran has said talks on monitoring cannot proceed until the threats end. With neither side moving, the IAEA’s ability to verify Iran’s program is likely to shrink further, and the Board of Governors meeting next week will be the first formal test of how member states respond.

Frequently asked questions

What is the Isfahan Fuel Enrichment Plant?

IFEP is an underground uranium enrichment plant at Isfahan, in central Iran, that Tehran declared to the IAEA on June 12, 2025. The agency has never inspected it, has not seen its design information, and says it does not know its exact location or whether it contains nuclear material.

How much enriched uranium does Iran hold?

The last figure the IAEA could verify was 440.9 kilograms of uranium enriched up to 60 percent purity, recorded on June 13, 2025. The agency says it has had no verified information about the stockpile since then, and cannot confirm that none of it has been diverted.

Why can’t IAEA inspectors visit Iran’s nuclear sites?

Iran has not allowed inspectors to return to any facility bombed in the June 2025 war, and told the agency this month that monitoring talks cannot proceed while the United States threatens further military strikes. The only site inspected since the war is the Bushehr power reactor.

What happens next?

The IAEA’s report is expected to be debated by its Board of Governors next week. Grossi has asked Iran to accept “technical and gradual measures” to let inspectors back in, and the agency says it is ready to resume work at short notice. Whether Tehran agrees will depend on whether the threat of new strikes eases.

The IAEA’s report leaves the world’s nuclear watchdog effectively blind inside Iran’s nuclear program, with its most sensitive stockpile unaccounted for and its newest enrichment plant uninspected. Until inspectors are allowed back — or the standoff over military threats is resolved — the agency says it cannot give the world the assurance it exists to provide: that Iran’s nuclear material has not been diverted from peaceful use.