US President Donald Trump has again threatened to strike a deeply buried Iranian nuclear facility still under construction, as tensions between Washington and Tehran escalate around the Strait of Hormuz.
The facility, called Kuh-e Kolang Gaz La — or “Pickaxe Mountain” — sits on the southern side of Iran’s Natanz nuclear enrichment complex. Natanz was targeted by the United States during Operation Midnight Hammer in 2025, amid the 12-day war between Iran and Israel.
Pickaxe Mountain, however, has not been hit, and Iranian work at the mountain site appears to be continuing.
What exactly Iran has installed there remains uncertain. The United Nations nuclear watchdog has never been granted access to inspect the site, leaving major questions about its purpose and progress.
Speaking to reporters in the Oval Office on Tuesday, Trump said Iran may have moved centrifuges into the mountain facility, possibly placing them so deep underground that even the most powerful bombs in the US arsenal could face a serious challenge.
“We’ll be hitting that area … probably pretty soon. And there’s not a thing they can do about it,” Trump said.
Last week, he also described Pickaxe Mountain as “a possible target for a nice big fat shot right near the front door.”
What to Know About Pickaxe Mountain
Here is what to know about Pickaxe Mountain, the Natanz nuclear site and the current state of Iran’s nuclear program.
The new project at Pickaxe Mountain is being constructed next to Natanz, about 140 miles south of Tehran, Iran’s capital.
Natanz, a mix of above and underground facilities, has been a point of international concern since its existence became known two decades ago.
Repeated sabotage attacks on Natanz, including one likely carried out by Israel that destroyed a manufacturing site for centrifuges, led Iranian officials to start work on the Pickaxe Mountain site.
Construction of the facility began in 2020, according to the ISIS thinktank, after what Iranian authorities reported at the time as an explosion caused by an act of sabotage at the Natanz site.
Tehran claimed at the time the Natanz sabotage had caused significant damage, and in September of that year, the country’s then nuclear chief, Ali Akbar Salehi, said the regime had started constructing a ‘modern, larger and more comprehensive hall in all dimensions in the heart of the mountain near Natanz’ for making advanced centrifuges.
Centrifuges, tube-shaped devices arranged in large cascades of dozens of machines, rapidly spin uranium gas to enrich it.
Experts Assess Underground Facility
Experts agree that the size of the project indicates Iran will likely be able to use the underground facility to enrich uranium as well as to build centrifuges, which produce nuclear fuel.
Additional cascades spinning would allow Tehran to quickly enrich uranium under the mountain’s protection.
Protected by anti-aircraft batteries, fencing and Iran’s paramilitary Revolutionary Guard, the facility sprawls across 2.7 square kilometres (1 square mile) in the country’s arid Central Plateau. It has multiple entrances visible from satellite images.
In 2023, an Associated Press story on Pickaxe Mountain included analysis from experts at the James Martin Center for Nonproliferation Studies that suggested Iran is likely building a facility at a depth of between 80 metres (260 feet) and 100 metres (328 feet).
Digging has continued at the site in the time since, with some experts suggesting it could be even deeper underground.
Such underground facilities led the US to create the GBU-57 bomb, which can plow through at least 60 metres (200 feet) of earth before detonating, according to the American military.
‘An attack on Pickaxe Mountain could target the above-ground incoming power supply lines, the location of ventilation shafts [the targets in the attacks in June last year] and the open tunnel entrances,’ the Washington-based Institute for Science and International Security said.
Tunnel Entrances in Focus
Satellite imagery suggests the site features two pairs of entrances and a security wall that was recently completed.
Since the US and Israel began launching strikes, a pair of eastern tunnel portal entrances has been hardened and partially backfilled to prevent ground vehicle access, but they have not been sealed completely, according to the ISIS thinktank.
Sam Lair, a fellow at the Foreign Policy Research Institute, told Reuters that increasing the strength of the tunnel entrances would complicate ‘targeting with penetrating munitions like bunker busters’.
The US president’s reference to striking the site ‘in the front door’ suggests any attack would aim to seal off the entrances rather than try to penetrate deep enough to demolish the underground caverns.
US officials reportedly have discussed using two such bombs in succession to ensure a site is destroyed.
It is not clear that such a one-two punch would damage a facility as deep as the one at Pickaxe Mountain.
Speaking alongside Lebanese President Joseph Aoun on Tuesday, Trump initially sought to downplay Pickaxe Mountain by bringing up Iran’s stockpile of highly enriched uranium.
Iran had enriched uranium up to nearly weapons-grade levels of 60 per cent before the 2025 strikes.
In the time since, Iran is not known to have restarted enrichment and its stockpile is believed to still be at the bombed enrichment sites.
‘We follow the material, that’s where the action is,’ Trump told journalists.
Pickaxe Mountain a Potential Target
Trump, however, said Pickaxe Mountain was a potential target for American bombers as back-and-forth attacks between Iran and the US rage on.
‘Normally I wouldn’t say that,’ the president added.
‘If I thought they could do something about it, I would never say that, but we’ll be hitting that area pretty soon. And very heavily.’
Iran says that areas around its only nuclear power plant at Bushehr have already come under attack during the war, though no damage was done to its Russian-run reactor.
Tehran also said the US attacked the cleared area where it plans to build the Darkhovin nuclear plant, though the UN’s International Atomic Energy Agency says there was no atomic material there the last time they inspected the site.
The only nuclear power plant in the United Arab Emirates, its four-reactor facility at Barakah, also has been targeted during the war.
Iran has since warned that it would take unspecified ‘required actions’ to respond to the Darkhovin attack.
In 2025, the US bombed Iran’s nuclear sites at Fordo, Isfahan and Natanz. All three had conducted uranium enrichment.
Iran’s Nuclear Program
At the time of the 2025 war and the recent Iran war, both Israel and the US said they aimed to stop Iran from ever being able to build a nuclear weapon.
Iran has long insisted its program is peaceful, and it isn’t believed by the IAEA or the West to have had an active military nuclear program since 2003.
Israel long has been believed to be the Middle East’s only nuclear-armed state.
However, even before the recent wars Iranian officials have increasingly threatened to pursue an atomic bomb.
The late Iranian Supreme Leader Ayatollah Ali Khamenei, killed February 28 in the opening moments of the war, issued a verbal fatwa, or religious ruling, that nuclear weapons were un-Islamic.
However, his son, Iran’s new Supreme Leader Mojtaba Khamenei, has not issued any statement regarding his views on the atomic bomb.
To build a usable weapon, Iran would first need to enrich uranium up to 90 per cent purity.
It would then need to build an actual bomb, and then likely also need to miniaturise it and mount it on a ballistic missile.
That process would take months or years, and would face the risk of discovery by Israeli or US intelligence in the meantime.
