Satellite images analysed by Sky News’ Data and Forensics team show Iran has fortified its nuclear and defence facilities, alongside conducting live drills with Russian forces amid rising tensions with the US military.
What we know about activity at Iran’s nuclear facilities
Iran appears to be fortifying defences at its nuclear plants and military facilities since strikes by Israel and the US in June 2025 damaged infrastructure at three key sites. Core enrichment activity remains constrained and under close international scrutiny.
The main sites affected by last year’s strikes were Fordow Fuel Enrichment Plant, Natanz enrichment facility and Isfahan Nuclear Fuel Complex. They are key to Iran’s core nuclear infrastructure.
The Isfahan Complex is in central Iran, 135 miles south of Tehran, near the city of Natanz. It is central to the nuclear fuel cycle, converting uranium into forms suitable for enrichment.
Isfahan includes an underground area where diplomats say much of Iran’s enriched uranium has been stored. Iran’s authorities have always said they are not trying to develop nuclear weapons.
Satellite images from 6 December 2025 to 24 January 2026 show structural repair and new efforts to bury tunnel entrances to the site.
Satellite images show “efforts to prepare for an attack” from the US, said David Albright, founder and president of the Institute for Science and International Security (ISIS) nonprofit.
He told Sky News: “At nuclear weaponisation sites, we see cleaning up and then, in some cases, rebuilding the facilities.”
He added: “You have this clear preparation in anticipation for attack, trying to minimise potential weak points.”
The ISIS institute reported on February 9 that “backfilling the tunnel entrances would help dampen any potential airstrike and also make ground access in a special force raid to seize or destroy any highly enriched uranium that may be housed inside difficult”.
At the Natanz nuclear facility, a site built for uranium enrichment, satellite images appear to indicate signs of construction at the Pilot Fuel Enrichment Plant, which was damaged by both US and Israeli air strikes in June.
Just over a mile from Natanz, there is a new site, Pickaxe Mountain, also known as Kolang Gaz La. Images show the construction and hardening of tunnel shafts.
Albright told Sky News: “At Pickaxe now, we can clearly see that they’ve taken steps to strengthen the tunnel entrances, which are a major vulnerability of these underground facilities.”
Deep inside a mountain near the city of Qom, around 90 miles south of Tehran, the Fordow fuel enrichment plant was also largely destroyed by the US, said Albright, with the entrance sealed up shortly after the 2025 strikes.
There has been “very little activity” there since, he said.
“From our point of view, some of these protection measures, particularly at Isfahan, indicates there’s something valuable still inside,” said Albright. “Whether it’s recoverable or not we don’t know.”
Other key military sites
Satellite imagery also shows Tehran repairing and fortifying other complexes essential to Iran’s operations.
Parchin military complex is one of Iran’s most sensitive military sites. It has been covered in concrete, as shown by satellite images from 24 January.
Reports suggest that 20 years ago, Tehran conducted tests linked to nuclear bomb detonation methods at the site. Tehran has consistently rejected this. Israel reportedly struck Parchin in October 2024.
On 22 January, an analysis by the Institute for Science and International Security (ISIS) pointed to progress in the construction of a “concrete sarcophagus” around a newly built facility at Parchin.
ISIS reported in November that imagery showed “ongoing construction and the presence of what appears to resemble a long, cylindrical chamber, maybe a high-explosives containment vessel, likely measuring approximately 36 meters long and 12 meters in diameter, placed inside a building”. It added that high-explosive containment vessels are critical for nuclear weapons.
It is not the only roof. Iran also built a roof over a destroyed facility at the Pilot plant to cover it and “hide activities”, said Albright.
Another site being repaired is Tabriz Missile Base in northwest Iran. The site is one of Iran’s principal missile launch and storage bases. Satellite images show buildings at the base have been fully repaired since the Israeli strikes in June 2025.
Iran’s military activity
On 19 January, Russian and Iranian forces conducted joint live drills in the Gulf of Oman and the Indian Ocean. Iran’s state-run IRNA news agency said the goal was “upgrading operational coordination as well as exchange of military experiences”.
Sky News has confirmed these drills were launched from Larak Island and Shahid Bahonar Port, both key strategic locations that control the Strait of Hormuz and Iran’s main naval hub. This highlights both Iran’s military readiness and influence over vital shipping routes.
Rear Admiral Hassan Maghsoodloo of the Iranian Navy told Iran International the drills were aimed at promoting security and sustainable maritime cooperation.
Mark Cancian, Senior Adviser from the Center for Strategic and International Studies (CSIS), suggested “Russia is trying to help its partner, but its capabilities are extremely limited because it is totally consumed with the war in Ukraine”.
The drills mirrored recent Iranian exercises on 16 and 17 February; the Islamic Revolutionary Guard Corps carried out naval and live-fire operations, including missile launches, across key shipping lanes such as the Strait of Hormuz.
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They occurred amid renewed negotiations between the United States and the Islamic Republic of Iran over Iran’s disputed nuclear program.
As talks opened, Iranian state media reported live missile fire toward the Strait, prompting its closure for several hours.
Iran often carries out military drills in the Strait of Hormuz, but the announced closure went a step further. Cancian said: “Closing the straits is hard, even impossible, without a lot more military capability. Iran could harass shipping with missiles and mines, though that would bring a response from many nations.”
Among all of this, Iran’s Supreme Leader Ayatollah Ali Khamenei posted a statement on X.
Iran’s naval assets
Sky News, using data from TankerTrackers, tracked several Iranian Navy vessels off the coast of Bandar Abbas on 16 January, including the drone carrier IRIS Shahid Bagheri, confirmed by satellite imagery about 10 km from shore. Frequently seen in this part of the Strait of Hormuz, the ship can deploy around 60 drones in addition to helicopters.
Mark Cancian, senior advisor at CSIS, stated that Shahid Bagheri was a “clever innovation” and the drone carrier is “part of that threat against the strait”.
Adding that Iran has been threatening the US by aiming the drone carrier directly at the USS Abraham Lincoln, a Nimitz-class aircraft carrier in the US Navy, capable of carrying dozens of aircraft, launching precision strikes, defending itself with advanced weapons, and coordinating naval and joint operations worldwide.
When asked if Iran’s naval assets were positioned to warn off the US, Cancian said: “Yes, the Iranian government is being aggressive rhetorically, and the naval movements, along with the joint exercise with the Russians, are meant to reinforce that.”
The Data x Forensics team is a multi-skilled unit dedicated to providing transparent journalism from Sky News. We gather, analyse and visualise data to tell data-driven stories. We combine traditional reporting skills with advanced analysis of satellite images, social media and other open source information. Through multimedia storytelling we aim to better explain the world while also showing how our journalism is done.
