UN confirms Assad's secret Syrian reactor could have produced nuclear weapons material

The toppled Syrian government of Bashar al-Assad built a nearly complete nuclear reactor in secret, designed to produce fissile material that could be fashioned into nuclear weapons. This revelation came this week from Rafael Grossi, the head of the International Atomic Energy Agency, the United Nations body responsible for monitoring nuclear activity worldwide. Grossi made the disclosure after IAEA inspectors visited two sites in Syria last month—one in the eastern province of Deir ez-Zor, where a reactor built with North Korean assistance had long been suspected, and a second location that Syrian authorities had only recently revealed to the agency.

The reactor's design was particularly efficient at producing weapons-grade material, Grossi explained to reporters gathered in Vienna. "They didn't want the world to know what they were doing," he said of Assad's regime, describing the construction as "a very important step" in what amounted to a clandestine nuclear weapons program. Syria had operated an extensive undeclared nuclear program under Assad's rule, though the full scope remained unclear until the regime's collapse in December 2024. The new Syrian government, seeking to rebuild international standing, granted IAEA inspectors access to these former nuclear sites—a cooperation that would have been unthinkable under Assad.

What inspectors found at the undisclosed location was striking in its concealment. Hidden behind walls and accessible only through narrow, difficult passages, they discovered approximately 73 tonnes of natural uranium metal in the form of fuel rods with protective cladding. The material had been scattered across the site in boxes, left essentially as it had been abandoned. Grossi described the physical challenge of the inspection: inspectors had to tear through walls and navigate cramped spaces to reach the uranium that Assad's government had deliberately hidden from international view.

The discovery of this uranium cache adds weight to a history of covert nuclear ambition that Israel had already exposed. In 2007, Israeli warplanes conducted a secret air raid on the Deir ez-Zor reactor site, destroying it before it became operational. The strike remained classified for eleven years until Israel publicly acknowledged it in 2018. Within months of that 2007 raid, U.S. officials had accused Syria of attempting to build a secret nuclear reactor and confirmed that Israel had destroyed it. Yet the existence of the uranium stockpile—and the second, previously unknown site—suggests Assad's nuclear ambitions extended beyond the single reactor that Israel had targeted.

The uranium itself is not immediately usable for a weapon. Logan Mintz, a nuclear materials security expert at the Nuclear Threat Initiative in Washington, explained that natural uranium metal could be "diverted to a covert weapons programme that further processes it into plutonium for a nuclear weapon." The material could theoretically be transported to another country in certified containers and converted into a more stable chemical form suitable for use in civilian nuclear power plants—a process that would require substantial security measures to prevent theft or sabotage.

For now, the IAEA has placed the uranium under international safeguards. Inspectors installed cameras at the site to maintain continuous monitoring, and Grossi emphasized that the agency would track the material "until the last gram." The question of what happens next—whether Syria retains the uranium or allows it to be removed to a third country for secure disposition—remains unresolved. Grossi made clear that the IAEA is not pushing the Syrian government in either direction. The decision belongs to Damascus, though any removal would require robust security protocols and international coordination. What is certain is that the material is no longer hidden, no longer beyond the reach of international inspection, and no longer available to a regime that saw nuclear weapons as an instrument of state power.