Iran reinforces tunnel defenses at Pikaks site, satellite images show

September 18, 2026 at 11:13 AM2 min

This digest was compiled by AI from multiple sources — links to the originals are below.

Iran has reinforced tunnel entrances at the Pikaks mountain site linked to its nuclear program, according to satellite imagery analyzed by the Washington-based Institute for Science and International Security. The images from September 11 show additional soil layers over tunnel entrances, increasing protection against airstrikes. The report comes a week after U.S. President Donald Trump warned Iran against activity at the site.

Key Facts

Satellite images from September 11 show additional soil layers over tunnel entrances at the Pikaks site, according to the Institute for Science and International Security.
The Pikaks mountain is located about two kilometers from Iran's Natanz nuclear facility.
Construction of the Pikaks underground complex began in 2020, with some parts estimated to be at least 100 meters deep.
Iran is also rapidly rebuilding the Taleghan 2 facility at the Parchin military complex, with satellite images from September 13 showing a tent covering the site and active construction equipment.
Israel struck Taleghan 2 in October 2024 and again in March 2026, after Iran had rebuilt and reinforced the complex.

Pikaks Tunnel Reinforcement

The Institute for Science and International Security (ISI) reported that satellite images from September 11 show an additional soil layer over one western tunnel entrance and several nearby entrances at the Pikaks site. The added soil increases the protective layer over the entrances and improves their resistance to airstrikes, according to American experts. The facility is not currently used for any work, but likely contains valuable equipment or materials, including centrifuges that could be used for uranium enrichment. The Pikaks mountain is about two kilometers from the Natanz nuclear site and contains several tunnels leading to a deep underground complex. Construction began in 2020, and analysts estimate some parts of the complex may be at least 100 meters below the mountain.

Trump Warning

The ISI data was released a week after U.S. President Donald Trump issued another warning about the Pikaks site. Trump told journalists last week that the U.S. notices some activity at the Pikaks facility and advised Iran not to play with fire, threatening a very powerful strike. Iranian officials have previously stated that a new underground facility is being built for the production of modern centrifuges. Iran claims no nuclear activity is conducted at the Pikaks site.

Taleghan 2 Rebuilding

In a separate report, ISI experts said Iran is rapidly rebuilding the Taleghan 2 facility at the Parchin military complex southeast of Tehran. Satellite images from Vantor Technologies dated September 13 show Iran covered the destroyed fortified facility with a tent, hiding work from satellite or aerial observation. Active construction activity around the site included dump trucks, bulldozers, concrete-laying equipment, and cranes. Iran also erected new concrete fortifications capable of providing additional protection from airstrikes, according to ISI experts. Israel struck Taleghan 2 in October 2024 and again in March 2026, after Iran had rebuilt and further reinforced the complex.