Iran's Uninspected Underground Nuclear Site Sparks Deep Concern Among Experts

The Institute for Science and International Security (ISIS), a prominent American research organization focused on Iran's nuclear ambitions, recently voiced significant apprehension regarding an uninspected underground facility within the Zagros Mountains. This covert location, identified as Pickaxe Mountain, has been inaccessible to inspectors from the International Atomic Energy Agency (IAEA).

This heavily fortified installation is generating considerable skepticism about Tehran's commitment to the stipulations of a memorandum of understanding (MOU) previously established with the Trump administration. The United States, in a joint effort with Israel, initiated Operation Epic Fury on February 28, 2026, specifically targeting Iran's nuclear and missile infrastructure.

Analysts at the Washington-based Institute for Science and International Security suggest that ceasing all activities at Pickaxe Mountain and granting IAEA inspectors unrestricted access would serve as a critical indicator of Iran's sincerity in moving away from its history of obfuscation.

Expert Concerns Over Covert Activities

Spencer Faragasso, a senior fellow at the institute specializing in Iran, North Korea, illicit trade, and nuclear proliferation, highlighted the issue on social media. He stated:

The ongoing work at Pickaxe Mountain is deeply concerning. This work has continued steadily since at least 2020. In my view, this is a hedge by Iran in case negotiations fail — they will then have a nuclear facility in a late stage of construction. We assessed that Pickaxe is likely large enough to hold an enrichment plant.

Historically, Iran has utilized sites such as Natanz, Fordow, and Esfahan for the enrichment of uranium, a crucial component for developing nuclear weapons.

Faragasso further commented on the situation, asserting:

If Iran is serious about negotiating, it should halt construction at Pickaxe Mountain as a token of good faith. But what can be expected from a regime as brutal and conniving as Iran’s?

Satellite Imagery Reveals Ongoing Construction

The institute recently published a comprehensive analysis of satellite imagery captured in late June 2026, which revealed persistent activity at the Pickaxe Mountain site.

According to the institute's report, "at Pickaxe Mountain, vehicle activity can be seen on the roads leading to the open set of Western tunnel portals, indicating that construction inside the tunnel complex, as well as hardening of the tunnel entrance, are ongoing." The analysis emphasized that the MOU between the United States and Iran mandates the preservation of the status quo, which should preclude any construction at nuclear-related facilities, including Pickaxe Mountain.

Monitoring Other Key Sites

In related findings, the institute noted that "as of June 29, 2026, there is no observed activity at Esfahan. The tunnel portals remain backfilled with dirt." Separately, ISIS has been closely monitoring developments at the Fordow facility, which is situated deep within a mountain north of the sacred city of Qom.

Regarding Fordow, the institute previously reported that between May 10 and May 18, Iran implemented passive defensive enhancements. These included the strategic placement of "earthen/rocky mounds and other objects on the roads leading to the tunnel entrances." The report detailed that "The alternating placements of the piles/objects are very precise, which creates a series of chicanes, indicating they are not intended as obstructions but rather to prevent rapid ingress and egress by any vehicle toward the tunnels."

Furthermore, the institute observed that a "June 21 Vantor image shows that the objects along the road remain there. The tunnel portals also remain backfilled with dirt," at the Fordow site.