VIENNA – In a confidential briefing distributed to member states and obtained by the Associated Press on Tuesday, the United Nations’ nuclear watchdog has formally confirmed that decades of unreported nuclear activity under former Syrian President Bashar Assad violated global non-proliferation rules.
Inspectors from the International Atomic Energy Agency (IAEA) carried out on-site verification work at multiple locations across Syria in August 2025, yielding new concrete evidence that the Assad regime failed to declare all nuclear material, facilities and activities as required under its Treaty on the Non-Proliferation of Nuclear Weapons (NPT) Safeguards Agreement.
The revelations center on a once-secret nuclear reactor project in the eastern Syrian region of Deir el-Zour, alongside a nearby fuel fabrication plant and an additional fuel storage site that were never disclosed to global regulators. For years, intelligence communities have alleged that Syria ran a large undeclared nuclear program, including the Deir el-Zour reactor constructed with technical support from North Korea.
Details of the reactor only emerged into public view in 2007, when Israel launched surprise airstrikes that destroyed the uncompleted facility. In the aftermath of the strike, the Assad regime bulldozed the entire site and consistently avoided providing full, transparent answers to IAEA investigators for nearly two decades. It was not until 2024 that IAEA sampling at the location detected particles of uranium, reigniting formal verification efforts.
During the August 2025 visit, inspectors returned to the Deir el-Zour site on August 29 to monitor ongoing excavation work. On-site observations have now confirmed that uncovered cooling infrastructure at the site matches the design specifications of a functional nuclear reactor. The report also identifies three additional locations that served supporting roles for the Deir el-Zour project: one dedicated to nuclear conversion and fuel fabrication work, a second for temporary storage of construction materials for the reactor, and a third that stored materials moved to and from the main site and was originally earmarked for future spent fuel reprocessing.
Beyond the long-investigated Deir el-Zour complex, the IAEA’s August inspection also included a previously undisclosed site that the new Syrian administration formally notified the agency of in a July 17 letter. The notification invited IAEA inspectors to conduct full verification of the site and any nuclear material found there.
To the agency’s surprise, verification work at the newly disclosed site found 73 tonnes of natural uranium metal formed into clad fuel rods, all of which had never been reported to the IAEA. As of the publication of the confidential report, all of this undeclared nuclear material has been placed under IAEA containment and continuous surveillance measures to prevent diversion for military use.
The confirmation of long-suspected undeclared nuclear activities comes amid a period of rapid political transition in Syria, marking one of the most significant findings by the IAEA regarding Middle Eastern non-proliferation compliance in nearly 20 years.