Construction and fortification work at a heavily protected Iranian site inside Mount Kolang near Natanz has accelerated sharply in 2026, according to an analysis of satellite imagery by the Washington-based Center for Strategic and International Studies (CSIS).
CNN reported that US officials continue to develop plans for a possible strike on the site, amid concerns that Iran could be preparing the facility as a protected location for its nuclear program. CSIS experts analyzed satellite images collected over six years, with the latest imagery dated August 9. They said activity at Mount Kolang during 2026 has exceeded anything recorded since the site was established.
The analysis identified intensified work on tunnel entrances and the internal road network, including the raising and fortification of tunnel portals, paving of roads, reinforcement of areas around the entrances and removal of excavation debris.
However, the experts said the imagery could neither confirm nor disprove Israeli intelligence reports that Iran has moved centrifuges to the site.
US President Donald Trump said in July that the United States would strike the facility “very soon and very hard,” but no such attack has taken place. The International Atomic Energy Agency has sought information from Tehran about Mount Kolang and requested access to the site.
According to CSIS, Iran has not responded to those requests. The experts said the facility’s location inside a deeply buried granite formation would make it difficult to destroy, even with the heaviest US non-nuclear conventional weapons.
