A prominent research organization says it has identified what appears to be a partially underground Iranian uranium-related site inside the Natanz nuclear complex, one of Iran’s most closely watched nuclear facilities.
The reported discovery is renewing questions about how much of Iran’s nuclear infrastructure survived the U.S.-Israeli military campaigns against the regime in 2025 and 2026, particularly elements tied to any potential nuclear weapons program.
The Institute for Science and International Security, a Washington, D.C.-based think tank often referred to as ISIS, said in late August that it had pinpointed an underground facility in Iran that is likely connected to uranium enrichment and could have relevance to the production of nuclear weapons material.
An illustration highlighting several of Iran’s nuclear sites, including the Arak heavy water reactor and the Natanz uranium enrichment plant. (FDD/Fox News)
In its assessment, the institute said the site “does not appear to have been targeted” during military operations in either 2025 or 2026. It also noted that available satellite images have shown no vehicle activity at the location since the June 2025 war.
According to the report, the institute identified a separately fenced, bunkered structure that is partly built below ground at the Natanz Nuclear Complex. Researchers said the building was likely designed as a uranium hexafluoride storage facility to support large-scale uranium enrichment at the Natanz Fuel Enrichment Plant. The structure was reportedly built between 2010 and 2017, with most of the work taking place from 2015 to 2017.
The institute argued that the finding carries a broader policy warning, saying any temporary prohibition on enrichment must go beyond a pause and require the dismantling and elimination of remaining capabilities, while also blocking preparatory work that could allow Iran to resume activity once a ban expires.
FILE – In this image released Nov. 5, 2019, by the Atomic Energy Organization of Iran, centrifuge machines are seen at the Natanz uranium enrichment facility in central Iran. (Atomic Energy Organization of Iran via AP, File)
Uranium is the crucial material to produce atomic weapons. Iran’s regime is vehemently opposed to the Trump administration’s demands that it stop enriching uranium and hand over its already enriched uranium.
According to another report by the Institute for Science and International Security in April,” From December 2024 to June 2025, a half-year period, Iran almost doubled its stock of 60% enriched uranium to 440 kilograms. This action dramatically increased suspicion that Iran was moving toward a decision to build nuclear weapons, significantly shortening timelines to be able to create a nuclear arsenal with up to ten nuclear weapons.”
The U.S. and Israeli strikes on Iran’s vast nuclear weapons facility during Operation Midnight Hammer in June 2025 significantly set back Iran’s ability to produce atomic weapons and enrich uranium.
Iran’s President, Masoud Pezeshkian, said they would rebuild the nuclear facilities targeted by the U.S., and make them stronger in 2025. (Iranian Presidency / Handout/Anadolu via Getty Images)
Jason Brodsky, policy director at United Against Nuclear Iran (UANI), told News Outlet that “The report assesses the structure at the Natanz nuclear facility was not targeted during Operations Midnight Hammer and Epic Fury. This raises questions as to why the U.S. and Israel did not target the site. Given that Iran is not allowing IAEA [International Atomic Energy Agency] inspections of bombed facilities, in contravention of its NPT [Treaty on the Non-Proliferation of Nuclear Weapons]obligations, this will require Washington and Jerusalem to rely on their own intelligence estimates as to this bunkered building.”
Brodsky added, “If it is still intact and can accommodate this kind of enrichment activity, the site should be destroyed in any future strikes. The allowance of such a facility under the JCPOA [Joint Comprehensive Plan of Action] demonstrates the flaws of the agreement — permitting Iran to retain an industrial scale enrichment program following the sunsets of various provisions — and underscores why zero enrichment in Iran has to continue to be the international demand.”
When asked about the facility and if the IAEA plans to inspect it, Fredrik Dahl, a spokesman for the IAEA, told News Outlet, that “The building you are referring to is well-known to the Agency as part of the Natanz site that the IAEA regularly inspected prior to mid-2025.”
This photo taken on May 15, 2023, shows the logo of the International Atomic Energy Agency IAEA at the IAEA headquarters in Vienna, Austria. TO GO WITH “Interview: IAEA chief expects wider, deeper nuclear cooperation with China.” (Liu Xinyu/Xinhua via Getty Images)
Asked about the report, Anna Kelly, a White House spokeswoman, told News Outlet that “First, Iran’s nuclear facilities were totally obliterated during Operation Midnight Hammer. Now, Operation Economic Outcast is severing every remaining economic lifeline sustaining the Islamic Republic of Iran. President Trump has been clear that Iran can never possess a nuclear weapon, and America is entering the endgame with the single greatest financial offensive ever mounted against an adversary.”
Successive U.S. administrations have repeatedly designated the Islamic Republic of Iran since the 1980s as a leading state-sponsor of terrorism.
U.S. Treasury Secretary Scott Bessent’s announcement last week that the U.S. imposed the economic equivalent of the military campaign that defeated Nazi Germany on the Islamic Republic of Iran could set off a series of events leading to the dissolution of the nearly 47-year-old dictatorship in Tehran, according to experts.
Bessent’s declaration of economic warfare — formally designated Operation Economic Outcast — follows President Trump’s commitment to launch an “economic D-Day” against the clerical regime. The comprehensive U.S. economic pressure point campaign also aims to isolate the regime with respect to its efforts to rebuild its nuclear weapons facility.
