A mysterious underground complex near Iran’s Natanz nuclear facility is attracting global attention after US President Donald Trump suggested on Tuesday that it could become the target of a military strike, with Trump claiming that uranium centrifuges could be located at the site.
“We’ll probably hit that area very soon. And they can’t do anything about it,” Trump told reporters at the White House.
Iran has threatened to “expand” the war if the US targets nuclear facilities.
Tehran has released almost no information about the complex, known as “Kuh-e Kolang Ghaz La” or Pickaxe Mountain in Persian.
Inspectors from the International Atomic Energy Agency (IAEA) have never been allowed inside, and most of what is known comes from satellite imagery and intelligence assessments rather than direct observation.
Although the site has surfaced repeatedly in reports over the years, its purpose remains unclear. That uncertainty has made it one of the most closely watched locations related to Iran’s nuclear activities.
What do we know about Pickaxe Mountain?
The underground complex is located south of Tehran in Iran’s Isfahan province, dug into a mountain about 2 kilometers (1.24 mi) from the Natanz uranium enrichment plant, one of the country’s most important nuclear facilities.
Commercial satellite images, including those published by Maxar Technologies, show continued construction since 2020.
They show the entrances to the new tunnels, 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 in Natanz in July 2020. Iranian officials described the explosion as an act of sabotage.
Months later, Tehran announced plans for a new underground facility where advanced centrifuges could be assembled in a more secure location. Officials said the replacement site would be larger, more advanced and better preserved than the damaged location.
The Washington-based Institute for Science and International Security estimates that parts of the facility may be buried 80 to 100 meters (330 ft) beneath the mountain.
If accurate, the complex would be deeper than many of Iran’s known nuclear sites and much more difficult to damage by air attack.
IAEA Director General Rafael Grossi has repeatedly said that agency inspectors have never been granted access to the site. Without inspection, the agency cannot verify whether nuclear material, centrifuges or other sensitive equipment is present.
Centrifuge report at Pickax Complex
In June 2026, wall street journal The report said Israeli intelligence assessed that Iran may have moved “thousands of uranium-enrichment centrifuges” components or other sensitive equipment to the complex in the months following the US and Israeli 12-day bombing campaign in June 2025.
Trump was asked about the report Tuesday, and he said Iran “may have” moved centrifuges to Pickaxe Mountain, but “we don’t have that on record.”
Some analysts also believe that 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 has always claimed its nuclear enrichment is for peaceful purposes and denies trying to build weapons.
International inspectors and intelligence reports have confirmed that Iran has about 970 pounds (440 kg) of uranium enriched to 60% purity, well above the level needed for civilian purposes and close to the 90% needed for weapons production.
Bomb-proof bunker?
Farzin Nadimi, a senior fellow at the Washington Institute for Near East Policy, told DW that Pickaxe Mountain’s strategic importance “lies in its resistance to bunker-buster bombs and its proximity to the Natanz nuclear complex.”
Nadimi argues that the damage caused to Iranian facilities in Fordow and parts of Natanz and Isfahan following the June 2025 bombing campaign has made the underground complex more important than before.
He said, “Given Iran’s security considerations, one should expect that future uranium enrichment and even weapons-related activities may eventually be concentrated in a single, highly protected location.” “Pickaxe Mountain is the most logical candidate for that role.”
Bunker-buster bombs used by the U.S. military are designed to penetrate terrain before exploding, but even the most powerful weapons among them can only penetrate to a certain depth.
Whether they could destroy a complex buried as deep 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.
Possibility of eliminating pickaxe feature
Unlike Natanz or Fordow, where key features have been identified for years, it is difficult to assess the damage caused to a target located inside a mountain.
Some analysts argue that if the site were ever targeted the objective would not be to destroy the entire complex. A more realistic military goal might be to demolish the tunnel entrances, damage access routes, or disable the supporting infrastructure, making it difficult or impossible to operate the facility.
Whether Pickaxe Mountain ultimately became a centrifuge production site, an enrichment facility or simply a heavily guarded support complex is unclear.
Its secrecy, location and apparent scale have turned it into one of the most closely watched parts of Iran’s nuclear program, likely to remain under close international scrutiny for years to come.
Edited by: Wesley Rahn