Israeli intelligence assesses that Iran transferred thousands of uranium-enrichment centrifuges into a deeply buried tunnel complex known as Pickaxe Mountain, located roughly a mile south of the Natanz nuclear site, according to a Wall Street Journal report citing Israeli and U.S. officials.

The transfer reportedly took place last fall, in the months following the June 2025 strikes on Iran’s nuclear infrastructure carried out under Operation Midnight Hammer.

Satellite imagery from late June 2026 shows vehicle activity at tunnel entrances carved into the mountain, which Iran refers to internally as Mount Kolang. The tunnels are believed to sit several hundred feet underground, a depth that would make the site far harder to damage in an airstrike than Iran’s previously targeted facilities.

The site has not been made available to International Atomic Energy Agency inspectors, and Iran has not disclosed its activity there, fueling concern that Tehran is positioning itself to resume enrichment even after the damage inflicted on Natanz, Fordow, and Isfahan last year. U.S. President Donald Trump has publicly named Pickaxe Mountain as a possible target, telling a radio interviewer the site was a candidate for further military action, while Prime Minister Benjamin Netanyahu has pressed for continued pressure on Iran’s weapons program.

Officials briefed on the intelligence caution that the full contents of the tunnel complex remain unverified, and that striking a target buried so deep would likely require specialized munitions or repeated strikes.