IAEA Confirms Surge in Construction Activity at Iran's Pickaxe Mountain Nuclear Site, Highest in Six Years

The International Atomic Energy Agency confirmed on September 10 that it has observed construction activity at Iran's Pickaxe Mountain, a heavily fortified underground site suspected of housing nuclear-related activities, with satellite imagery indicating new movement at the site just south of Tehran's main Natanz uranium-enrichment plant, IAEA Director General Rafael Grossi told Bloomberg Television. A new analysis by the Center for Strategic and International Studies examined six years of satellite imagery and found that construction activity in 2026 is higher than at any previous point observed at the site, CNN reported.

CSIS said the imagery reveals a clear three-phase activity signature indicating a site that has shifted from active excavation toward probable internal construction and continued exterior reinforcement, including hardening tunnel entrances, paving internal roads, reinforcing access points, and removing excavated soil. The analysts said the imagery cannot confirm Israeli intelligence claims that Iran moved uranium centrifuges into the facility, and the site does not currently appear to be operating as an enrichment facility based on the absence of certain observable activity. The IAEA has requested information about Pickaxe Mountain and access to the facility, but Iran has reportedly never responded to IAEA requests.

US President Donald Trump has threatened military action against Pickaxe Mountain at least twice in the past week, warning Iran not to get cute there and noting a little activity at the site. CNN reported the US awarded a prototype contract in September 2025 for a new bunker-buster munition that would succeed the GBU-57A/B Massive Ordnance Penetrator and could potentially target more deeply buried facilities. On September 7, the IAEA board referred Iran to the UN Security Council for the first time in 20 years for failure to cooperate in an investigation into uranium traces detected at undeclared sites. Pickaxe Mountain is located j

Sources

Sources: Bloomberg, CNN, Times of Israel, Jerusalem Post, Arab News, Gulf News, Iran International, CSIS, Crypto Briefing, Eurasia Review. IAEA Director General statements verified. Satellite analysis from CSIS and Institute for Science and International Security.