Imagery Update: Makeshift Roadblocks Installed in Front of the Esfahan Underground Complex Tunnel Entrances
High resolution Airbus satellite imagery from April 8, 2026, shows that Iran has newly constructed makeshift roadblocks in front of all three tunnel entrances leading into the underground facility at the Esfahan Nuclear Complex, which is believed to be where Iran has stored the majority of its highly enriched uranium. The additional passive defensive measures were added at some point on or after March 18, 2026. All three tunnel portals remain backfilled with dirt and no effort has been made by Iran or anyone else to clear them and regain access.
The establishment of roadblocks (including earthen berms, rubble piles, and a possible chicane and fencing at the northern entrance) are likely intended to further restrict any freedom of movement towards the tunnel complex and add additional complexity to any ground operation to enter the tunnel complex and seize the enriched uranium likely to be stored there. The roadblocks can be removed by using bulldozers or backhoes, but this will add to the timetable necessary to clear the tunnel portal entrances and establish ground access.
According to International Atomic Energy Agency (IAEA) Director General Rafael Grossi, the Esfahan underground complex is believed to hold at least half of Iran's stockpile of 60 percent highly enriched uranium (equivalent to roughly 220 kg), enough material to produce weapon grade uranium for five nuclear weapons. Iran also declared to the IAEA in June 2025 that it was building a new enrichment facility known as the Esfahan Fuel Enrichment Plant. The location and status of this enrichment plant are unknown, but it is suspected to be inside the tunnel complex.
Figures 1 - 4 provide close-ups of the new passive defense measures at the individual entrances, as well as an overview of the tunnel complex and its three entrances.
Southern Tunnel Portal
The southernmost tunnel entrance (where the transport of 18 possible HEU containers was observed just prior to the June 2025 War)[1] has two roadblocks along the road leading up to the tunnel entrance, one consisting of a 2-meter-wide mound of dirt, and another built from unidentified material (see Figure 1). Additionally, two parked cars can be seen at the security checkpoint leading to the southern tunnel portal, a further indicator of ongoing activity and security monitoring at the site as well as serving as additional roadblock, something we have observed periodically since June 2025 (see Figure 4).
Middle Tunnel Portal
The middle tunnel entrance area (which includes an adjacent probable utilities alcove whose entrance is also buried) has one fully constructed dirt pile roadblock and an additional one under construction on the main road leading to the backfilled tunnel portal (see Figure 2). Another new barricade can be seen blocking the entrance to the probable utilities’ alcove, as well as what appears to be a chicane consisting of three small barriers next to a pre-existing probable checkpoint. The entire middle entrance area is fenced off next to that probable checkpoint and across both portal road accesses Near the middle tunnel portal, an unidentified piece of equipment can be seen on the ground, possibly a piece of machinery. The machinery is likely to be used to further reinforce the dirt backfill, rather than clear it to enable access to the tunnel portal. A new unidentified object measuring roughly 2.7 meters long was placed on top of the dirt pile backfilling the tunnel portal.
North Tunnel Portal
At the northernmost tunnel portal, a large dirt pile can be seen blocking the former primary road leading to the tunnel portal itself and two more roadblocks can be seen on the bypass road, one consisting of a dirt pile and another made from miscellaneous rubble/debris (see Figure 3). The fence gates, on both the original primary entrance road and the bypass road, remain closed.
Figure 1. A view of the southernmost tunnel entrance at the Esfahan Nuclear Complex shows a before and after of the recent passive defensive changes.
Figure 2. A before and after view of the middle tunnel portal entrance showing the new passive defensive measures installed.
Figure 3. A before and after view of the northernmost tunnel portal entrance. Prior to being backfilled with dirt, satellite imagery shows that Iran had opened the doors to this tunnel portal.
Figure 4. Overview of the tunnel complex, with security checkpoints identified in the before image (top, March 18, 2026) and new roadblocks in the after image (bottom, April 8, 2026).