The International Atomic Energy Agency confirmed on September 10, 2026, that satellite imagery shows ongoing construction and movement at Iran’s Pickaxe Mountain facility, a deeply buried site located next to the country’s main uranium-enrichment complex at Natanz. The confirmation came one day after the Center for Strategic and International Studies published an analysis documenting road traffic and structural work at the site at levels well above anything previously recorded.

At the same time, the IAEA Board of Governors referred Iran’s nuclear dossier to the UN Security Council for non-compliance. It was the first such referral in roughly two decades.

What the satellite images show—and what they do not

IAEA Director General Rafael Grossi described the indicators of activity at Pickaxe Mountain but emphasized the limits of the agency’s knowledge. Despite repeated requests, no IAEA inspector has ever entered the facility’s underground tunnels.

Satellite imagery can show trucks, freshly poured concrete, and expanded road networks. It cannot establish what is being built, stored, or processed more than 100 meters underground.

The CSIS analysis, published on September 9, 2026, concluded that the scale of recent construction activity at Pickaxe Mountain exceeded anything observed in previous years. According to the organization’s measurements, both road-traffic volume and structural enhancements reached unprecedented levels.

Pickaxe Mountain is located between 1.5 and 2 kilometers south of the Natanz enrichment facility. Construction there began in the fall of 2020, shortly after reported sabotage incidents damaged infrastructure at Natanz.

Iran’s explanation and Western concerns

Iranian authorities have characterized Pickaxe Mountain as a site for producing and assembling advanced centrifuges. Western intelligence agencies, however, have expressed concern that a facility more than 100 meters underground, situated beside a known enrichment complex and deliberately shielded from international inspection, could more plausibly be used for the secure storage of nuclear materials or covert enrichment activity.

The IAEA has sought access to the site without success since at least mid-2025. The agency’s last confirmed inspection access occurred before that period, meaning inspectors have had no verified view inside the tunnels for at least a year.

The Nuclear Non-Proliferation Treaty and Iran’s safeguards agreement with the IAEA require Tehran to provide inspectors access to declared facilities and, in some circumstances, undeclared facilities. Refusing access constitutes a compliance issue in its own right, separate from whatever may be taking place underground.

Security Council referral raises diplomatic pressure

The Board of Governors’ decision to refer Iran’s nuclear file to the Security Council carries significant diplomatic weight, although the Council’s record on enforcing measures against Iran is complicated by the veto power of Russia and China.

The previous time the Board took this step was approximately two decades ago, before the 2015 Joint Comprehensive Plan of Action. The nuclear agreement briefly placed Iran’s enrichment activity under tighter controls before the United States withdrew from it in 2018.

Grossi’s public confirmation of activity at Pickaxe Mountain on the same day as the referral indicates that the agency is coordinating its disclosures carefully. Presenting satellite-confirmed evidence of increased construction while escalating the matter to the Security Council increases pressure on Tehran to explain the site’s purpose or grant the access it has so far denied.