Experts reviewing satellite images said in a report on Tuesday that Iran is reportedly building a nuclear facility so deep underground that even the most powerful American-made weapons may not be able to destroy it.

The report, published by the Associated Press (AP), spoke with several nuclear experts and analyzed satellite images to reach its conclusions. A major clue to the nature of the new facility, reportedly located in the Zagros Mountains of central Iran near the existing Natanz nuclear site, is the heavy construction of tunnels leading deep under a feature known as “Pickaxe Mountain.”

Satellite images reveal at least four large tunnel entrances leading under the mountain, each at least 20 feet wide and 26 feet high. The size of the dirt piles near these tunnels led the AP’s analysts to conclude a large facility is being excavated at least 260 feet underground and possibly even deeper depending on how far along the construction effort has come.

Judging by the size of the tunnel entrances and the distance between them, the facility appears large enough to contain the centrifuge cascades that Iran would need to enrich uranium to weapons-grade levels. It is buried deep enough to protect it against even the massive GBU-57 bomb, a weapon the U.S. designed to take out bunkers and nuclear facilities up to 200 feet underground.

Iran has acknowledged that it is building an underground nuclear facility in the area to replace the uranium centrifuge manufacturing plant at Natanz that was damaged by a mysterious explosion and fire in July 2020. 

Overview from January 5, 2021, of the construction plan for a future underground centrifuge assembly facility south of the Natanz uranium enrichment site.

Iranian officials initially downplayed the extent of the damage, at one point suggesting the fire broke out in a mere “industrial shed,” but later admitted the production of advanced centrifuges would be significantly “delayed.”  

Iran claimed the Natanz underground facility was sabotaged in April 2021, damaging its uranium centrifuges. Iran blamed the sabotage on Israeli agents.

Israeli National Security Adviser Tzachi Hanegbi quickly responded to the AP report, saying on Tuesday he was not surprised by Iran’s new construction project — and not at all convinced that the buried facility would be immune to attack.

“What is possible to say about this matter is that there is no place that can’t be reached,” Hanegbi said at a security conference held near Tel Aviv.

“We hope we won’t get to a situation where the solution to the story of a nuclear weapon in Iran is a kinetic solution, a solution involving an attack,” he added.

“There are possible negative developments on the horizon and that can bring about action. We have capabilities. Others have capabilities, and this is a very significant and important matter,” said Israeli military commander Lt. Gen. Herzi Halevi, who spoke at the same conference.