IAEA Detects Activity at Mount Kolang Gaz La; Trump Warns: 'We May Have to Hit Iran Very Hard'

The International Atomic Energy Agency said today (Thursday) that it had identified construction activity at Mount Kolang Gaz La in Iran, an underground site near the Natanz nuclear complex. IAEA Director General Rafael Grossi said in an interview with Bloomberg: "There are indications that there is movement around this construction site." However, he emphasized: "We have no concrete information regarding activities that may be taking place there."

The comments came after U.S. President Donald Trump warned Iran following activity detected in the area: "We may have to hit there. We cannot allow Iran to have nuclear weapons. It’s very simple." In a speech at the Republican conference ahead of the midterm elections, he added: "We see that there is some activity at Mount Kolang Gaz La. I would advise Iran not to get smart, because we will have to hit them very hard."

The site, located about 225 kilometers south of Tehran and buried beneath a mountain near Natanz, has been at the center of intelligence attention in recent months, amid concerns that Iran may use it to secretly revive its nuclear program.

According to an analysis of satellite images by the Center for Strategic and International Studies (CSIS), 2026 saw a "clear increase in construction activity" at the site. The work appears to have moved from a phase of "active excavation" to "internal construction work and continued external reinforcement."

The site has also seen "more road activity than ever before" this year. Among other things, tunnel entrances were raised and reinforced, an internal road network was paved, access areas were strengthened, and soil removed during excavations was cleared away.

According to the assessments described in the report, the facility was likely designed as a safe haven for Iran’s nuclear program. However, the ongoing construction and other factors indicate that the site is still not capable of enriching uranium.