‘Surge in construction’ at suspected Iranian nuclear site, analysts say, as US considers ways to strike deep underground

Key Points:

• Satellite imagery analysis by CSIS reveals a significant increase in construction activity in 2026 at Pickaxe Mountain, a suspected underground Iranian nuclear site near Natanz, likely intended as a secure location for Iran's nuclear program.
• Israeli intelligence and US officials, including former President Trump, have expressed concerns about Iran potentially relocating centrifuges to Pickaxe Mountain, with Trump threatening imminent strikes against the site.
• The granite composition of Pickaxe Mountain makes it a challenging target for existing US bunker-busting bombs, prompting the Pentagon to develop next-generation penetrator weapons capable of striking deeply buried facilities.
• In early 2026, the Defense Threat Reduction Agency awarded an emergency contract to prepare a subterranean test site at White Sands Missile Range for live-fire testing, likely aimed at validating new capabilities against Iran's fortified underground nuclear sites.
• Despite ongoing construction and reinforcement at Pickaxe Mountain, analysts suggest the facility may not yet be operational for uranium enrichment, reflecting Iran's continued efforts to harden and expand its nuclear infrastructure amid escalating tensions.