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Natanz tunnel reinforcements
Satellite images analyzed by BBC Verify and the BBC Persian fact-checking section show Iran strengthening a tunnel complex near the Natanz nuclear facility, with construction activity to reinforce the entrances of two tunnels called Kalang Gazla (or Kuh Kalang) in Isfahan Province.
“Iran is strengthening a tunnel complex near the Natanz nuclear facility”
The BBC reported that based on satellite imagery analysis dated 21 Bahman (February 10), fresh concrete appears to have been poured on one of the entrances of the mountain slope, and that analysts from the Institute for Science and International Security and the information analysis firm Mayer confirmed that a pump for transferring concrete is visible at the site.
The BBC also said that in another tunnel entrance within this complex, rock and soil have been backfilled and leveled, and that a new structure reinforced with reinforced concrete has been built nearby.
Analysts from the Institute for Science and International Security believe these changes were made to strengthen the tunnel entrances and provide greater protection against air strikes, and the BBC reported that the ongoing presence of heavy construction machinery and materials suggests the facilities are probably not yet ready for operation.
Sina Asadi, director of the Middle East Studies program at George Washington University, told BBC Persian that Iran is acting on the assumption that attacks will occur, and therefore must protect its facilities as much as possible, saying: "The Iranian nuclear program has not been destroyed."
Pickaxe Mountain and IAEA
Fox News said inspectors from the International Atomic Energy Agency (IAEA) have not been allowed to visit the secret site known as Pickaxe Mountain, describing it as a highly fortified facility in the Zagros Mountains that is casting serious doubt on Iran’s willingness to abide by the terms of a memorandum of understanding (MOU) reached with the Trump administration.
Fox News quoted Spencer Faragasso, a senior fellow at the Washington-based Institute for Science and International Security, writing on X: "The ongoing work at Pickaxe Mountain is deeply concerning."
Fox News also reported that the institute posted a detailed analysis of new satellite imagery from late June 2026 showing continued activity at Pickaxe Mountain, including that "vehicle activity can be seen on the roads leading to the open set of Western tunnel portals" and that construction inside the tunnel complex and hardening of the tunnel entrance are ongoing.
The Fox News account said the MOU signed between the United States and Iran requires Iran maintain the status quo, which should prohibit construction at any nuclear-related facility, including Pickaxe Mountain.
In the same Fox News report, it added that in late June the IAEA declined to answer a detailed Fox News Digital query on whether it would seek access to the Pickaxe Mountain facility.
Talks, uranium, and protection
The BBC reported that these developments occur as Iran and the United States recently held talks in Oman, with talk of a second round of negotiations, but tensions between the two countries continue to rise.
“"we have a window of opportunity, but windows of opportunity tend to close suddenly and quickly"”
Rafael Grossi, the IAEA Director General, told BBC that reaching a new nuclear agreement between Iran and the United States may be possible and is urgently needed, saying: "we have a window of opportunity, but windows of opportunity tend to close suddenly and quickly".
The BBC also said Grossi believes about 400 kilograms of highly enriched uranium remains in tunnels and underground facilities—the same places where the United States bombed them in the summer.
In a separate report, Iran International said the Institute for Science and International Security reported defensive actions at the underground Klang Gazla site south of the Natanz facilities, with the two eastern tunnel entrances partially blocked with gray soil materials to prevent vehicle entry.
Iran International reported that the think tank said these facilities lie at a very great depth and could be used to protect valuable equipment or materials, and it added that earlier this calendar year there were indications that entrances to the old tunnel complex dating back to 2007 in Klang Gazla Mountain were covered with soil and reinforced with concrete.
