Iran's Pickaxe Mountain has emerged as the latest flashpoint in the US-Iran nuclear standoff, as both US and Israeli intelligence agencies believe Iran has shifted parts of its nuclear programme to the heavily fortified mountain after last year's strikes, raising fresh concerns over Tehran's nuclear ambitions.
The underground complex, located about two kilometres south of the Natanz nuclear facility, has also drawn the attention of US President Donald Trump, who has repeatedly suggested it could become the target of future military action.
According to a Wall Street Journal report, US and Israeli officials believe Iran moved thousands of uranium enrichment centrifuges to the site after key nuclear facilities were damaged during the June 2025 conflict. The report has renewed concerns in Washington and Jerusalem that Iran is attempting to preserve and rebuild its nuclear capabilities beyond the reach of future military strikes.
Why Does Pickaxe Mountain Matter?
The renewed focus on Pickaxe Mountain comes after the United States and Israel launched strikes on Iran's nuclear facilities at Natanz, Fordow and Isfahan during the 12-day conflict last year under "Operation Midnight Hammer."
The International Atomic Energy Agency (IAEA) later confirmed that Natanz's above-ground enrichment plant was destroyed, while its underground facility suffered significant damage. According to intelligence shared by Israeli officials with Washington, Iran responded by relocating surviving centrifuges and other sensitive equipment to the tunnel network beneath Pickaxe Mountain to protect its uranium enrichment programme from future attacks.
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The Washington-based Institute for Science and International Security (ISIS) has also said the mountain complex remained untouched during the military campaign. The think tank has estimated that between 400 kilogrammes and 450 kg of uranium enriched to 60% survived the earlier strikes and has not been publicly accounted for. The organisation also believes Pickaxe Mountain is one of the most likely storage locations, although there is no independent confirmation.
Though the underground shifting of uranium might be after the recent US attack, the construction of the underground complex began after an explosion destroyed Natanz's above-ground centrifuge assembly hall in 2020. Iran later announced plans to build a larger and more advanced facility inside the mountain.
Since then, the Satellite imagery has shown continuous excavation, reinforced tunnel entrances and heavy construction activity. Analysts believe parts of the facility are buried more than 100 metres beneath solid granite, making it deeper than the Fordow enrichment plant.
Because of its depth and reinforced structure, defence experts say the complex would be extremely difficult to destroy using conventional air strikes. Even the US GBU-57 Massive Ordnance Penetrator, commonly known as a bunker-buster bomb, may struggle to reach the deepest underground chambers.
IAEA Still Waiting for Access
Although Iran informed the IAEA in 2021 that nuclear-related work was planned at the site, inspectors have not been granted access to verify what is taking place underground. The UN nuclear watchdog had said that it has not been allowed to inspect Pickaxe Mountain despite growing intelligence assessments. The lack of independent inspections means satellite imagery and intelligence reports remain the primary sources of information about the facility.
Now, with Washington and Israel convinced that Iran is rebuilding elements of its nuclear programme inside Pickaxe Mountain, and Tehran continuing to restrict international access, the underground complex has become one of the most closely watched sites in the Middle East-and a potential focus of any future US military campaign.
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