53 minutes ago
10
The UN’s nuclear watchdog has confirmed that construction is picking up at one of the most closely watched and least accessible sites in Iran’s nuclear program. Pickaxe Mountain, an underground complex located roughly 1.5 to 2 kilometers south of the Natanz uranium enrichment facility, is showing fresh signs of building activity, according to the International Atomic Energy Agency.
IAEA Director General Rafael Grossi acknowledged the activity in a September 10, 2026, interview, while noting that inspectors have never set foot inside the facility. The agency has been limited to satellite imagery for its assessments.
What we know about Pickaxe Mountain
Construction at the site began in fall 2020, reportedly triggered by sabotage at Natanz’s above-ground enrichment facility.
The complex features tunnel entrances designed to reach halls buried at least 100 meters beneath the mountain.
Satellite analyses from independent organizations, including the Institute for Science and International Security and the Center for Strategic and International Studies, show a noticeable uptick in construction-related work throughout 2026. Paved roads, hardened entrances, and expanded access networks are all visible from orbit.
No verified evidence has been presented confirming the presence of nuclear material or active enrichment at the site. The facility does not appear to be operational yet.
The inspection gap
Iran has consistently rejected requests for information access, maintaining that its nuclear program serves exclusively peaceful purposes.
Grossi was candid about the limits of remote monitoring, noting the absence of definitive insights into internal activities without inspector access.
In June 2025, US and Israeli strikes targeted Iranian nuclear facilities. Pickaxe Mountain, notably, remained untouched during those operations. One day after the strikes, the IAEA Board of Governors referred Iran’s nuclear file to the UN Security Council for non-compliance.
The military dimension
US President Donald Trump has publicly expressed concerns about the site, hinting at the possibility of military action as tensions escalate.
The Security Council referral introduces a formal diplomatic channel, but Russia and China, both permanent members with veto power, have historically been reluctant to impose harsh new measures on Tehran.
Disclosure: This article was edited by Editorial Team. For more information on how we create and review content, see our Editorial Policy.
English (US) ·