Satellite imagery reviewed by a Washington nuclear watchdog shows continued construction at Iran’s most secretive nuclear site even as Tehran sits across the table from American negotiators, raising the question of whether the regime is preparing a hedge against the very diplomacy it claims to be pursuing in good faith.
The Institute for Science and International Security (ISIS) reported that Iran’s underground Pickaxe Mountain complex, buried inside the Zagros Mountains near Natanz, remains under active construction, and that the International Atomic Energy Agency has never once been permitted to inspect it. The assessment, based on imagery captured in late June, comes as the Trump administration works to implement the memorandum of understanding reached with Iran following Operation Epic Fury, the joint US-Israeli military campaign launched February 28 against Iran’s nuclear and missile infrastructure.
According to ISIS, the late-June photographs show vehicles entering the western tunnel portals at Pickaxe Mountain along with fresh fortification work at the entrances, indicating that construction inside the mountain has not stopped. The institute argues that this activity is incompatible with the memorandum of understanding, which is meant to require Iran to preserve the status quo at nuclear-related sites until inspection and verification measures are completed.
Spencer Faragasso, an ISIS senior fellow who tracks Iran’s nuclear program, wrote on X that the project appears designed to give Tehran <cite index=”0-8″>”a hedge by Iran in case negotiations fail”</cite>, leaving the regime with a nuclear facility already in an advanced stage of construction should talks collapse. Faragasso said Iran could prove its sincerity by freezing work at the site and opening it to inspectors, a step the regime has so far refused to take.
The Pickaxe Mountain tunnel complex, known in Iran as Kuh-e Kolang Gaz La, is believed to have been under construction since 2020. Its exact purpose has never been confirmed, since the IAEA has never been granted access. ISIS reported persistent activity at the site since April, when a ceasefire took hold in the war between Iran and the US-Israeli coalition. Since then, Iran has partially filled several tunnel portals to block vehicle access while sealing off a smaller tunnel complex within the site’s perimeter, the contents of which remain unknown but could include enriched uranium.
Elsewhere in Iran’s nuclear infrastructure, the picture is one of paralysis rather than progress. At Natanz itself, the underground enrichment halls remain inaccessible, with destroyed entrances, wrecked power systems, and displaced HVAC chillers still unrepaired since the strikes of June 2025. At Fordo, Iran has added earthen barriers near tunnel entrances that ISIS believes are designed to prevent a rapid military raid aimed at seizing the uranium stockpile stored inside. At Isfahan, where most of Iran’s 440-kilogram stockpile of uranium enriched to 60 percent is believed to be held, according to the IAEA, tunnel entrances remain blocked and no new activity has been observed.
Outside the nuclear sphere, Iran has moved with far greater urgency. The regime has already rebuilt entrances to 50 of 69 tunnel openings across 18 underground missile facilities damaged in the war, along with access roads struck by American and Israeli aircraft. Iran is believed to still possess roughly 1,000 ballistic missiles stored in those sites.
Israel is not a party to the memorandum of understanding and has criticized the document for extracting no concrete concession from Iran on its nuclear program. Negotiations toward a permanent ceasefire between the United States and Iran are expected to resume in Pakistan on July 11, with Iran’s nuclear program, sanctions relief, and the IRGC’s frozen assets all on the agenda.
