At the centre of the imagery analysis is the Parchin military complex, located about 30 kilometres southeast of Tehran. Western intelligence agencies have long alleged that experiments related to nuclear weapons development took place there more than two decades ago, a claim Iran has consistently denied.

Israel reportedly struck the site in October 2024. Satellite photographs taken before and after the alleged strike show heavy damage to a rectangular building, followed by reconstruction efforts visible in November 2024 images. By October 2025, a skeletal framework of a new large structure had appeared alongside two smaller adjacent buildings. In mid-November imagery what appeared to be a metal roof covered the structure.

However, more recent images show the facility gradually disappearing from view. Photographs from December reveal partial covering of the site, and by mid-February the structure is no longer visible. Analysts from the Institute for Science and International Security (ISIS) say the building has been encased within a concrete covering, then concealed under layers of soil.

ISIS previously reported that satellite images showed what resembled a long cylindrical chamber within the facility, possibly a high-explosives containment vessel- measuring roughly 36 metres in length and 12 metres in diameter. Such vessels can be associated with nuclear weapons development but may also be used in certain conventional weapons research.

Imagery analysts say the roof of the structure blends closely with its surroundings, suggesting soil was added to reduce visibility and obscure the distinctive colour of reinforced concrete. The development, they argue, would likely enhance protection against aerial strikes.

Tunnel entrances buried at Isfahan nuclear site

Elsewhere, satellite photos also reveal changes at the Isfahan nuclear complex, one of three uranium-enrichment facilities struck by the United States during Israel's 12-day conflict with Iran last year.

The complex includes both fuel-cycle installations and underground sections where diplomats believe enriched uranium may have been stored. Images taken in late January indicate that Iran began backfilling at least two tunnel entrances with earth. A subsequent update showed a third entrance similarly covered.