President Trump has renewed warnings that the U.S. Could bomb Iran’s fortified Pickaxe Mountain nuclear site as fresh satellite imagery shows Tehran accelerating construction at the underground facility.
The Washington-based Center for Strategic and International Studies, a prominent think tank, released findings last week from a six-year satellite analysis of the mountain fortress near Natanz. Researchers concluded that construction activity at the site shot up dramatically in 2026, with visible work on portal accesses, internal roads, and reinforcement around entry points.
“There is a clear surge in construction activity in 2026 that corresponds to the raising and hardening of the portal accesses, paving of the internal road network, reinforcement around access areas, and the flattening and removal of excavation spoil,” the CSIS wrote in its latest report.
The acceleration began around October 2025, according to the CSIS findings. That timing roughly coincided with Israeli intelligence warnings to the Trump administration that Iran was allegedly relocating uranium centrifuges and components to the underground base. The think tank did not independently verify the Israeli claim about centrifuge movement.
Trump, 78, has seized on the facility’s growing threat in recent public remarks. “We may hit Pickaxe very soon,” he told reporters last week.
The mountain’s depth presents the central military challenge. Pickaxe Mountain sits buried at least 328 feet beneath Kolang Mountain, potentially beyond the reach of America’s most powerful conventional bunker-buster. The GBU-57 penetrator can dig through roughly 200 feet of earth and rock before detonating, leaving an estimated 130-foot gap to the facility’s deepest sections.
American weapons developers are currently pursuing next-generation penetrator bombs, with secret tests examining performance against the same stone composition found at Pickaxe Mountain. The development timeline and testing status of these weapons remain unclear.
Iran continued construction at Pickaxe Mountain even during a temporary cease-fire period covered by a memorandum of understanding with the U.S., the CSIS analysis found. That ongoing work violated the terms of the truce, researchers noted.
“CSIS imagery analysis confirms that construction activity continued at a high rate during the period covered by the MOU,” the think tank wrote.
The site remains incapable of enrichment operations at this stage, according to the assessment. However, Iran appeared to be conducting “internal construction” at the deep mountain base, suggesting preparation for future nuclear work.
Military planners face limited options for neutralizing the facility. The U.S. Could target entrance points in an effort to bury the site, a tactic previously employed against Iranian missile facilities. Experts have cautioned that Iran has repeatedly demonstrated its ability to excavate and reopen buried bases.
The June 2025 war marked a major escalation in the long-running confrontation over Iran’s nuclear program. The U.S. And Israel conducted coordinated bombing strikes against Iranian nuclear sites during that conflict, damaging above-ground infrastructure but apparently failing to destroy deeply buried facilities like Pickaxe Mountain. The subsequent construction surge suggests Tehran is racing to fortify what survived and expand its underground sanctuary before any renewed hostilities.
Along with digging out entrances damaged or buried in the earlier attacks, Iranian crews appear focused on hardening those access points against future strikes.