Satellite photos show activity at Iran nuclear sites as tensions rise over protest crackdown

Those coverings block satellites from seeing what’s happening on the ground — right now the only way for inspectors from the International Atomic Energy Agency to monitor the sites as Iran has prevented access.

Iran has not publicly discussed the activity at the two sites. The IAEA, a watchdog agency of the United Nations, did not respond to requests for comment.

U.S. President Donald Trump repeatedly has demanded Iran negotiate a deal over its nuclear program to avert threatened American military strikes over the country’s crackdown on protesters. The U.S. has moved the USS Abraham Lincoln and several guided-missile destroyers into the Middle East, but it remains unclear whether Trump will decide to use force.

The new roofs do not appear to be a sign of reconstruction starting at the heavily damaged facilities, experts who examined the sites said. Instead, they are likely part of Iran’s efforts “to assess whether key assets — such as limited stocks of highly enriched uranium — survived the strikes,” said Andrea Stricker, who studies Iran for the Washington-based Foundation for Defense of Democracies, which has been sanctioned by Tehran.

“They want to be able to get at any recovered assets they can get to without Israel or the United States seeing what survived,” she said.

Isfahan and Natanz are 2 key Iran sites

Prior to Israel launching a 12-day war with Iran in June, the Islamic Republic had three major nuclear sites associated with its program. Iran long has insisted its nuclear program is peaceful. However, Iranian officials in recent years have increasingly threatened to pursue the bomb. The West and the IAEA say Iran had an organized nuclear weapons program up until 2003.

The Natanz site, some 220 kilometers (135 miles) south of the capital, is a mix of above- and below-ground laboratories that did the majority of Iran’s uranium enrichment.

Before the war, the IAEA said Iran used advanced centrifuges there to enrich uranium up to 60%, a short, technical step from weapons-grade levels of 90%. Some of the material is presumed to have been onsite for when the entire complex was attacked.

The facility outside the city of Isfahan was mainly known for producing the uranium gas that is fed into centrifuges to be spun and purified.

A third site, Fordo, some 95 kilometers (60 miles) southwest of the capital, housed a hardened enrichment site under a mountain.

During last year’s war, Israel targeted the sites first, followed by U.S. strikes using bunker-busting bombs and Tomahawk cruise missiles. The U.S. strikes “significantly degraded Iran’s nuclear program,” the White House’s National Security Strategy published in November said, though specifics on the damage have been hard to come by publicly.

Iran has not allowed IAEA inspectors to visit the sites since the attacks.

Roofs seen in Isfahan and Natanz

The main above-ground enrichment building at Natanz was known as the Pilot Fuel Enrichment Plant. Israel hit the building June 13, leaving it “functionally destroyed,” and “seriously damaging” underground halls holding cascades of centrifuges, the IAEA’s director-general, Rafael Mariano Grossi, said at the time. A U.S. follow-up attack on June 22 hit Natanz’s underground facilities with bunker-busting bombs, likely decimating what remained.

Planet Labs PBC images show Iran began in December to build a roof over the damaged plant. It completed work on the roof by the end of the month. Iran has not provided any public acknowledgment of that work. Natanz’s electrical system appears to still be destroyed.

Iran also appears to be continuing digging work that it began in 2023 at Kūh-e Kolang Gaz Lā, or “Pickaxe Mountain,” a few hundred meters (yards) south of the Natanz complex’s perimeter fence. Satellite images show piles of dirt from the excavation growing in size. It is believed to be building a new underground nuclear facility there.

At Isfahan, Iran began building a similar roof over a structure near the facility’s northeast corner, finishing the work in early January. The exact function of that building isn’t publicly known, although the Israeli military at the time said its strikes at Isfahan targeted sites there associated with centrifuge manufacturing. The Israeli military did not respond to requests for comment over the construction.

Meanwhile, imagery shows that two tunnels into a mountain near the Isfahan facility have been packed with dirt, a measure against missile strikes that Iran also did just before the June war. A third tunnel appears to have been cleared of dirt, with a new set of walls built near the entrance as an apparent security measure.

Sarah Burkhard, a senior research associate for the Washington-based Institute for Science and International Security, which long has watched Iran’s nuclear sites, said the roofs appear to be part of an operation to “recover any sort of remaining assets or rubble without letting us know what they are getting out of there.”

Sean O’Connor, an expert at at the open-source intelligence firm Janes, concurred that the aim was likely “to obscure activity rather than to, say, repair or rebuild a structure for use.”

Other work continues in Iran

Since the end of the war, Iran has worked to reconstitute its ballistic missile program, rebuilding sites associated with the program, earlier AP reporting showed. That’s included work at a military complex known as Parchin, just to the southeast of Tehran.

In recent weeks, Iran has been working to rebuild a site at Parchin identified by the Institute for Science and International Security as “Taleghan 2.” Israel destroyed the site in an airstrike in October 2024.

It has said an archive of Iranian nuclear data earlier seized by Israel identified the building as housing an explosive chamber and a special X-ray system to study explosive tests. Such tests could be used in research toward compressing a core of uranium with explosives — something that’s needed for an implosion-style nuclear weapon.

Satellite photos show construction being done at “Taleghan 2” in recent months. The open-source intelligence firm Janes similarly noted the construction, as did the institute.

“This has been reconstituted very rapidly,” said Lewis Smart, a Janes analyst who studies Iran’s nuclear program. “It’s being expanded to potentially make it more resistant to penetration attacks and bombings. ... A rather large containment vessel is being put into the facility, which could be used for high explosive testing.”

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