A mysterious underground complex near Iran’s Natanz nuclear facility is attracting global attention after former U.S. President Donald Trump suggested on Tuesday that it could become the target of a military strike, claiming that uranium centrifuges might be located there.
“We’ll be hitting that area very probably pretty soon. And there’s not a thing they can do about it,” Trump said in remarks to reporters at the White House.
Iran has warned that it would “expand” the conflict if the United States strikes nuclear facilities. Tehran has released virtually no information about the complex buried beneath what is known in Farsi as “Kuh-e Kolang Gaz La,” or Pickaxe Mountain.
Inspectors from the International Atomic Energy Agency (IAEA) have never been permitted inside, and much of the knowledge about the site comes from satellite imagery and intelligence assessments rather than direct observation. Although the facility has appeared in reports over the past few years, its purpose remains unclear, making it one of the most closely monitored locations linked to Iran’s nuclear activities.
What do we know about Pickaxe Mountain?
The underground complex lies south of Tehran in Iran’s Isfahan province, carved into a mountain roughly 2 kilometers (1.24 miles) from the Natanz uranium enrichment plant, one of the country’s most important nuclear facilities.
Commercial satellite imagery, including images from Maxar Technologies, shows continuous construction since 2020. The images reveal new tunnel entrances, access roads, security installations, and large quantities of excavated rock. Construction appears to have accelerated after an explosion damaged Iran’s advanced centrifuge assembly workshop at Natanz in July 2020, an event Iranian authorities described as sabotage. Months later, Tehran announced plans for a new underground facility where advanced centrifuges could be assembled in a more secure location, stating that the replacement site would be larger, more advanced, and better protected than the damaged one.
The Washington-based Institute for Science and International Security estimates that parts of the facility may be buried 80 to 100 meters (330 feet) beneath the mountain. If accurate, the complex would be deeper than many of Iran’s known nuclear sites and considerably more difficult to damage with an air strike.
IAEA Director General Rafael Grossi has repeatedly said that agency inspectors have never been granted access to the site. Without inspections, the agency cannot verify whether nuclear material, centrifuges, or other sensitive equipment are present.
Reports of centrifuges in the Pickaxe complex
In June 2026, The Wall Street Journal reported that Israeli intelligence assessed that Iran may have transferred “thousands of uranium-enrichment centrifuges” components or other sensitive equipment to the complex in the months following the 12-day bombing campaign conducted by the United States and Israel in June 2025.
When asked about the report on Tuesday, Trump said that Iran “may have” moved the centrifuges to Pickaxe Mountain, but “we don’t have it on record.”
Some analysts also believe the complex could eventually support the production or assembly of advanced centrifuges if Iran decides to restore or expand those capabilities.
Iran has consistently argued that underground facilities are necessary to protect its nuclear infrastructure from sabotage and military attack. Tehran maintains that its nuclear enrichment program is for peaceful purposes and denies seeking to produce a weapon.
International inspectors and intelligence reports confirm that Iran possesses approximately 970 pounds (440 kg) of uranium enriched to 60% purity, far above the level needed for civilian use and approaching the 90% required to produce weapons.
Bomb-proof bunker?
Farzin Nadimi, a senior fellow at the Washington Institute for Near East Policy, told DW that the strategic importance of Pickaxe Mountain “lies in its resistance to bunker-buster bombs and its proximity to the Natanz nuclear complex.” Nadimi argues that the reported damage to Iran’s facilities at Fordo and parts of Natanz and Isfahan after the June 2025 bombing campaign has made the underground complex more important than before. He added, “Given Iran’s security considerations, one should expect that future uranium enrichment and even weapon-related activities could eventually be concentrated in a single, heavily protected location. Pickaxe Mountain is the most logical candidate for that role.”
What we know — and don’t know — about Iran’s nuclear program
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The bunker-buster bombs used by the U.S. military are designed to penetrate terrain before detonating, but even the most powerful of those weapons can only reach a certain depth.
Whether they could destroy a complex buried as deeply as Pickaxe Mountain remains a matter of debate among military experts. The exact layout of the tunnels, their depth, and the location of any critical infrastructure have never been made public.
Chance of crippling the Pickaxe facility
Unlike Natanz or Fordo, where key facilities have been identified over the years, it is difficult to assess damage to a target located inside a mountain. Some analysts argue that if the site were ever targeted, the objective might not be to destroy the entire complex. A more realistic military goal could be to collapse tunnel entrances, damage access routes, or disable supporting infrastructure, making the facility difficult or impossible to operate.
Iran defies US pressure over nuclear, missile plans
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Whether Pickaxe Mountain eventually becomes a centrifuge production site, an enrichment facility, or simply a heavily protected support complex remains unclear.
Its secrecy, location, and apparent scale have turned it into one of the most closely watched pieces of Iran’s nuclear program, which is likely to remain under close international scrutiny for years to come.
Edited by: Wesley Rahn
