The International Institute for Science and Security (IISS) has stated that its latest assessment of Iran’s nuclear facilities shows no significant activity at the Natanz site. Access to the underground enrichment chambers remains closed, and the main and backup power systems, as well as HVAC equipment, are still offline.
At the Koh Kolang complex, vehicles were observed on the entrance path to the western tunnels, suggesting ongoing construction and reinforcement work, while the eastern tunnel entrances remain blocked by soil. Similarly, at the Farav site, soil and rock obstacles continue to impede access to the tunnels.
In Isfahan, no new activity has been detected as of June 29, 2026, and the tunnel entrances are still blocked. The report also notes that Iran’s enriched uranium storage was located within the same complex.