In a comprehensive assessment of Iran’s safeguards implementation, the International Atomic Energy Agency presents clear evidence that Iran violated its safeguards obligations but finds no evidence of a current, illicit nuclear program. The IAEA’s findings underscore the urgent need for a nuclear deal that brings Iran back into compliance with its legally binding safeguards obligations and limits its future proliferation risk.
The May 31 report, requested by the Agency’s Board of Governors in November 2024, provides greater context and information about the years-long investigation into four locations where Iran conducted nuclear activities and housed materials that were never declared to the agency, as required by Iran’s safeguards agreement. The IAEA concludes, unsurprisingly, that three of the sites under investigation “were part of an undeclared structured nuclear programme carried out by Iran until the early 2000s and that “some activities used undeclared nuclear material.”
Critically, the report also assesses that there are “no credible indications of ongoing, undeclared structured nuclear programme.”
The IAEA's assessment that Iran is not currently pursuing an illicit nuclear weapons program is supported by U.S. intelligence community findings. So there is still time for negotiating an agreement that reduces Iran’s proliferation risk. But that time is short. As the IAEA warns, Iran is rapidly advancing its uranium enrichment program, including accelerating the production of uranium enriched to near weapons-grade levels. Tehran’s nuclear advances underscore the urgent necessity of an effective, verifiable nuclear deal that limits Iran’s future proliferation risk and holds Tehran accountable for full implementation of its safeguards agreement.
Clear Evidence of Undeclared Activities
The May 31 report makes a clear, compelling case that Iran failed to meet its legally binding safeguards obligations under the Nuclear Nonproliferation Treaty (NPT). It connects the undeclared nuclear activities at some of the sites under investigation to activities Iran conducted prior to 2003 that are relevant to weaponization—but the report is not revelatory.
Rather, the IAEA provides further detail about what was already known: Iran conducted illicit nuclear activities in violation of its safeguards agreement as part of a covert nuclear weapons development program and has failed to account for all of the nuclear materials that were used as part of that effort. These are serious issues and must be addressed, but they are not an indication of whether or not Iran intends to develop nuclear weapons in the future.
Iran has argued, unconvincingly, that the IAEA’s current investigation is an attempt to reopen the agency’s probe into past weaponization work, the so-called possible military dimensions (PMD) of Iran’s nuclear program. That investigation was closed in December 2015, as part of the nuclear deal between Iran and the P5+1, or Joint Comprehensive Plan of Action. The May 31 report does connect the activities under investigation to the weaponization-relevant work that was assessed in the PMD report, but it is not a re-opening of the weaponization file.
In investigating evidence of undeclared nuclear materials and activities at Marivan, Varamin, Turquzabad, and Lavisan-Shian, the IAEA is fulfilling its nuclear material accountancy mandate and holding Iran accountable to its safeguards obligation. That these activities occurred in the past and had ties to a closed investigation does not excuse Iran from cooperating with the IAEA to account for the nuclear materials.
Addressing these current safeguards questions does not require Iran to confess to the pre-2003 illicit nuclear weapons development effort that officials continue to deny exists, only to provide the IAEA with the information necessary to determine if all materials are accounted for.
It is in Iran’s interest to resolve these accountancy questions and fully implement its safeguards agreement. So long as nuclear materials remain unaccounted for in Iran, it will drive speculation that Tehran is still engaged in illicit nuclear activities and could undermine the sustainability of a future nuclear deal between the United States and Iran.
Implications for Diplomacy
The United States, with the backing of European countries, is reportedly considering a resolution censuring Iran for its failure to cooperate with the agency and finding it in violation of its safeguards commitments. The censure would build off of previous resolutions requiring Iran to comply with the IAEA.
Tehran must be held accountable for its safeguards violations, but pushing for a resolution at the upcoming meeting of the IAEA Board of Governors, while the United States and Iran still are engaged in talks to develop a formula to curb Iran's sensitive nuclear activities, risks fracturing the fragile diplomatic progress made to date. Iran is almost certain to perceive a censure, however justified, as a provocation and respond, as it has done before, by ratcheting up its nuclear activities or reducing cooperation with the agency.
Given that Iran is sitting on the threshold of nuclear weapons and officials are openly debating the security value of a nuclear deterrent, any escalatory spiral could kill the negotiating process and increase the risk of conflict. As the IAEA reports highlight, Tehran is better positioned to move quickly toward nuclear weapons, given its expanding uranium enrichment program and the relevance of past weaponization work. Both sides must show restraint in responding to this report and remain focused on negotiations.
The Trump administration has a narrow window of opportunity to reduce the urgent proliferation risk posed by Iran’s nuclear program. It is critical for the United States to pursue a deal based on clear, pragmatic objectives: rolling back Iran’s most proliferation-sensitive nuclear activities and implementing intrusive monitoring and verification measures.
Reaching a deal should not let Iran off the hook for cooperating with the agency. As part of this process or in parallel to it, Iran must address the IAEA’s questions about undeclared nuclear activities. Implementing and sustaining an effective nuclear deal requires confidence that Tehran is fully meeting its safeguards obligations and that its nuclear materials are accounted for.—KELSEY DAVENPORT