The Washington-based Institute for Science and International Security published satellite imagery analysis dated June 29, 2026, showing sustained construction activity at Pickaxe Mountain, an undisclosed underground facility in Iran's Zagros Mountains that International Atomic Energy Agency inspectors have not been permitted to enter. The finding raises direct questions about Iranian compliance with the memorandum of understanding reached with the Trump administration, which explicitly requires Tehran to maintain the status quo at all nuclear-related sites. The United States and Israel launched Operation Epic Fury on February 28, 2026, targeting Iran's nuclear and missile capabilities.
Pickaxe Mountain: Activity Since at Least 2020
ISIS assessed that construction inside the Pickaxe Mountain tunnel complex has continued steadily since at least 2020. New satellite imagery showed vehicle activity on roads leading to the open set of western tunnel portals, with hardening of the tunnel entrance also ongoing. Spencer Faragasso, a senior fellow at ISIS who covers Iran, North Korea, illicit trade, and nuclear issues, characterized the activity as a hedge by Iran — a facility being advanced to a late stage of construction in case negotiations collapse. ISIS assessed the site is likely large enough to house an enrichment plant. Iran has used facilities at Natanz, Fordow, and Isfahan for uranium enrichment.
The IAEA declined in late June to respond to a detailed query about whether it would seek access to the site. The State Department and the Iranian Mission to the United Nations had not responded to questions from Fox News Digital as of publication.
Damage Assessment at Natanz, Fordow, and Isfahan
Satellite imagery provided a site-by-site status of Iran's known nuclear facilities following Operation Epic Fury. At Natanz, ISIS observed little activity: access points to the below-ground enrichment halls remain unrepaired, personnel entrances remain destroyed, and vehicle entrances remain severely damaged. A single vehicle was visible outside the Pilot Fuel Enrichment Plant, which was destroyed in June 2025 and subsequently covered by Iran. At Isfahan, ISIS reported no observed activity as of June 29, 2026, with tunnel portals remaining backfilled with dirt.
Fordow Defensive Measures Remain in Place
At Fordow, buried inside a mountain north of Qom, ISIS tracked the placement of passive defensive measures between May 10 and May 18, 2026. Iran positioned earthen and rocky mounds along roads leading to the tunnel entrances in a precise, alternating pattern, creating a series of chicanes. ISIS assessed the arrangement is not intended as an obstruction but rather to prevent rapid vehicle ingress and egress toward the tunnels. A June 21 image from Vantor confirmed the objects remained in place, with tunnel portals continuing to show backfill.
Compliance Test
Faragasso framed access to Pickaxe Mountain as the threshold good-faith measure for the current negotiations. ISIS argued that halting construction and admitting IAEA inspectors would constitute a meaningful signal of Iran's willingness to break from its prior pattern of concealment. The MOU's status-quo clause, as interpreted by ISIS, covers Pickaxe Mountain despite the site never having been formally disclosed to international monitors.