The Iranian nuclear site buried under Pickaxe Mountain has seen an increased level of construction work over the last year, analysts reviewing satellite imagery shared with CNN on Wednesday.

Construction at the site, analysts from the Center for Strategic and International Studies (CSIS) think tank told CNN, “has shifted from active excavation toward probably internal construction and continued exterior reinforcement.”

The site has seen “more road activity,” as well as “raising and hardening of the (tunnel) portal accesses, paving of the internal road network, reinforcement around access areas, and the flattening and removal” of excavated dirt.

According to CSIS, the site has likely been designed to be a safe haven for Iran’s nuclear program, CNN reported.

CSIS analysts said that the site could serve as a centrifuge assembly facility, an enrichment facility, or other “nuclear-weapons-relevant” work. However, based on the continuous construction, the analysis estimated that the site “is not yet capable of enrichment work, if that is the intended purpose.”

A source familiar with the matter told CNN that the United States had considered Pickaxe Mountain one of the potential targets if the war against Iran escalated in the last several months.

One source said that the Defense Department had recently held a “planning sprint” on the topic of strikes against Iranian underground facilities, including Pickaxe Mountain.

US explores options for striking deeply buried Iranian sites

Pickaxe Mountain could prove difficult to strike with existing US non-nuclear bombs due to the granite surrounding the underground facility, according to the CSIS analysis cited by CNN.

Four days before the US launched Operation Epic Fury, a Defense Threat Reduction Agency program manager signed an emergency $1.2 million contract justification for repairs to an underground test facility at White Sands Missile Range in New Mexico, CNN reported.

The document referred to preparations for a live-fire test of classified capabilities and said the work needed to be completed within two to three weeks due to a “time-sensitive national security directive.”

Three sources told CNN that the planned test was connected to the Iran war and efforts to develop ways of targeting Iran’s deepest underground facilities.

CNN said it could not independently verify whether the test occurred or confirm the purpose of activity observed at the White Sands site.

US developing next-generation penetrator

The US struck Iranian nuclear sites during Operation Midnight Hammer in June 2025. A top US general later told lawmakers that only the entrances to the deeply buried Isfahan nuclear site were buried because the Pentagon believed its Massive Ordnance Penetrator bombs could not destroy the facility, CNN reported.

The US military is also developing a successor to the Massive Ordnance Penetrator that could potentially target more deeply buried facilities.

A prototype contract was awarded in September 2025, and the Air Force sought defense industry sources for the weapon in June, CNN reported.

CNN also reported that the US maintains operational plans to strike Pickaxe Mountain. The site was included in a target package considered earlier this summer, although it remains unclear whether existing US munitions could penetrate deeply enough to destroy what Iran may have moved underground.

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