UN nuclear watchdog urges Iran to reopen its atomic sites as inspectors remain locked out

The watchdog’s patience runs out over a plant it has never seen

The United Nations nuclear watchdog has told Iran to take “incremental steps” towards letting its inspectors back into the country’s key atomic sites, warning that access is “critical” and that verification must resume “without further delay”. The appeal came in a report by the International Atomic Energy Agency (IAEA) circulated among member states on Friday, 13 November, and seen by the AFP news agency.

The agency has not had access to key Iranian nuclear facilities since Israel, joined by the United States, launched a 12-day conflict in June 2025 that included strikes on nuclear sites. Facilities were hit again in the war that erupted on 28 February, and the IAEA has repeatedly called for access ever since.

At the centre of the report is a plant the agency has never set foot in. Iran told the IAEA in June 2025 that it was building an underground uranium enrichment facility near Isfahan, in central Iran, and initially agreed to let inspectors visit. The visit was cancelled after Israel launched its attacks the following day, and no inspector has been allowed in since. Tehran has been reviewing proposals on its nuclear programme for months, but the inspections question has barely moved.

The plant, the stockpile and the paper trail

The Isfahan Fuel Enrichment Plant, known as IFEP, is the sharpest edge of the report. The IAEA says it does not know the plant’s exact location, whether it contains nuclear material, or what its status is under international monitoring rules. The report did not establish that uranium enrichment is taking place there; the point is that the agency cannot establish anything at all.

The same blindness covers the stockpile. Before the June 2025 strikes, Iran had accumulated about 440 kilograms of uranium enriched to 60 percent purity, according to the IAEA; close to the 90 percent needed for a weapon, and far above the 3.67 percent limit set by the now-defunct 2015 nuclear agreement, which also capped the stockpile at 300 kilograms. Since the strikes, the fate of that material has remained uncertain. The agency’s director general, Rafael Grossi, said in June that the “widespread impression” was that the stockpile remained where it was before the strikes, near the Isfahan plant.

The nuclear complex at Isfahan suffered extensive damage in the American and Israeli strikes, particularly the visible parts of the site. The condition of its underground facilities is not clear, and the IAEA believes much of Iran’s highly enriched uranium was stored there.

The institutional record is equally stark. In September, the IAEA board referred Iran to the UN Security Council, the first time Iran has been sent to the Council in 20 years for failing to meet its nuclear reporting obligations. The agency withdrew its inspectors for safety reasons, and Iran later passed a law suspending cooperation with it. Even so, the report notes that the IAEA is “fully prepared to resume its safeguards activities in Iran at short notice”. Iran has insisted, including from hardline voices at home, that it remains committed to the Non-Proliferation Treaty, and Foreign Ministry spokesman Esmaeil Baghaei repeated that commitment at a news conference in Tehran on Monday; while blaming the American and Israeli attacks for the limits on cooperation.

What the report cannot tell us about Isfahan

First, the plant itself. The IAEA does not know where exactly the Isfahan enrichment plant sits, whether it holds nuclear material, or whether any enrichment is under way inside it. An underground facility that has never been visited is, for verification purposes, a blank space on the map.

Second, the stockpile. The agency cannot verify the status of roughly 440 kilograms of uranium enriched to 60 percent. It believes much of it was stored at Isfahan, but belief is not verification, and the report is explicit that the agency cannot conclude that no declared nuclear material has been diverted from peaceful use.

Third, the underground damage. The strikes wrecked the visible parts of the Isfahan complex, but nobody outside Iran has seen what happened below the surface; not the agency, and not the governments that ordered the strikes. Until inspectors return, every claim about what survived, what was destroyed and what was moved rests on satellite pictures and inference rather than measurement.

A verification gap at the heart of the non-proliferation system

The IAEA’s inspections exist for one purpose: to verify that nuclear material is not diverted towards weapons. When the agency cannot get into a country’s facilities, that assurance collapses, and the gap itself becomes the story. The report calls the lack of information “a matter of serious proliferation concern” that “needs to be rectified with the utmost urgency”; the strongest language the agency has used about Iran in months.

The stakes reach beyond the file. Uranium enriched to 60 percent is a short technical step from weapons grade, and the uncertainty over where it sits, and in whose hands, shapes the calculations of every government in the region; Israel, which says it struck to prevent a weapon; the Gulf states, which live within range of any escalation; and the United States, whose president has publicly threatened further strikes. Talks over who might hold Iran’s uranium have already involved Russia as a possible custodian, a sign of how far the diplomacy has had to reach for a workaround.

There is also a precedent at stake. If a state can absorb two rounds of strikes and then keep the world’s inspectors out indefinitely, the safeguards system that underpins the Non-Proliferation Treaty loses its central tool; and other states will be watching how that ends.

Verification is the dispute now, not just the uranium

What has changed is the shape of the argument. A year ago the argument was about how much uranium Iran held and how fast it was enriching. Today the argument is about whether anyone will ever be allowed to check. The report’s central proposal, “technical and gradual measures”, is a deliberately modest one: not a grand bargain, but a sequence of small steps that could put inspectors back inside a building without either side conceding the larger point.

That modesty is also its weakness. Tehran has tied inspections to the end of American threats, and Washington has shown no sign of withdrawing them. The IAEA board’s referral to the Security Council adds pressure, but the Council’s last twenty years suggest it can condemn more easily than it can compel. The most likely outcome is a long negotiation about the conditions of access; conducted while the stockpile sits unmeasured and the plant at Isfahan stays unseen.

What the blind spot unlocks next

The first consequence lands in the Gulf, where governments that have spent the year hedging between Washington and Tehran must now price a new uncertainty: a neighbour whose nuclear inventory is unknown to the world’s inspectors, in a region where two wars have already been fought over it in seventeen months.

The second lands on the diplomacy itself. With verification stalled, the proposals Tehran has been reviewing, and the question of who might hold its uranium, become harder to close, because no deal can be verified without inspectors, and no inspector can enter without a deal on security.

The third is slower and wider. The safeguards system rests on the idea that inspections are routine, technical and non-negotiable. A state that keeps inspectors out for more than a year, through two wars, tests whether that idea survives contact with force; and every other government with a nuclear programme is reading the result.

What happens when the file reaches the Security Council?

The report now goes to the IAEA’s member states, and the next moves belong to the board and the Security Council. The board referred Iran once already, in September; the question is whether the Council will act on a file it has not touched in twenty years. Tehran’s next reply will be watched for any opening on the “technical and gradual measures” Grossi proposed; a partial inspection, a visit to a single site, a concession framed as a safety measure rather than a surrender. The IAEA says it is ready to return at short notice. The question is whether anyone will give it a door to walk through.