The International Atomic Energy Agency (IAEA) issued a report on Tuesday rebuking Iran for withholding access to two sites of concern and for failing to answer questions about those two sites and one other. Iran’s refusal to cooperate sets up a potential clash with the IAEA Board of Governors that could escalate toward action by the UN Security Council.

According to the IAEA’s report, the sites the agency seeks to access relate to “possible undeclared nuclear material and nuclear-related activities in Iran,” which the IAEA is obligated to investigate according to Iran’s legally binding Comprehensive Safeguards Agreement (CSA), and predates the nuclear deal. Concealing undeclared nuclear material and denying inspection access to the IAEA could also constitute a breach of Iran’s obligations under the Nuclear Non-Proliferation Treaty (NPT), whose authority the regime continues to acknowledge.

To justify its refusal to cooperate with inspectors, Iran presented a tendentious interpretation of the 2015 nuclear deal, formally known as the Joint Comprehensive Plan of Action (JCPOA). The deal required Tehran to implement a roadmap aimed at resolving unanswered questions regarding the possible military dimensions (PMD) of its nuclear activities. Although Iran proceeded to stonewall the PMD investigation, the IAEA Board of Governors passed a resolution in December 2015 that removed the PMD investigation from the agency’s agenda. Iran now claims this December 2015 decision exempts its pre-JCPOA conduct from further scrutiny. Thus Iran told the IAEA it “will not recognize any allegation on past activities and does not consider itself obliged to respond to such allegations.”

Subsequent revelations have made clear just how ill-advised the Board of Governors’ decision was in December 2015. In early 2018, the Israeli government shared information with the IAEA indicating that a warehouse in Tehran’s Turquzabad district contained nuclear-related equipment and material relevant to past and possibly ongoing nuclear weapons efforts. But during the summer of 2018, Iran emptied the site of its contents and carried out concealment and sanitization activities. After substantial delay, the IAEA finally visited the site in the spring of 2019 and managed to collect uranium samples.

Also in 2018, Israeli intelligence seized a half-ton of documents from a separate storage facility in Tehran detailing a well-coordinated nuclear weapons program called the Amad Plan. The archive, whose contents date mostly to the pre-2004 period, contained evidence of previously unknown sites aimed at producing weapons-grade uranium for an initial set of five nuclear weapons. The files also disclosed an effort by Tehran to disguise, hide, and continue sensitive activities after 2004.

The IAEA has been analyzing the archive’s materials and likely pinpointing sites of concern that it wants to visit, leading to Iran’s denials of access to the two sites mentioned in Tuesday’s report. The materials in the archive point to a connection between the uranium particles collected by the IAEA at Turquzabad and undeclared uranium conversion efforts from the time period prior to 2004 that is discussed in the archive.

Under new Director-General Rafael Grossi, the IAEA has returned to investigating pre-JCPOA matters of concern and highlighting Iran’s basic safeguards obligations. This shift is also reflected in the Board of Governors’ agenda for its meeting during the week of March 9, which includes a separate agenda item for the implementation of NPT safeguards in Iran, in addition to the item dedicated to the JCPOA. The IAEA is effectively reasserting its authority to investigate any issue covered by the CSA and Iran’s other verification agreement, the Additional Protocol.

The IAEA Board of Governors should support the IAEA’s continued investigation and calls for immediate access to any site in Iran that it needs to visit. If Iran does not cooperate, the Board should refer the matter to the UN Security Council for countermeasures. Time is of the essence for the Security Council to consider reinstituting UN sanctions and restrictions lifted by the nuclear deal.

Andrea Stricker is a research fellow at the Foundation for Defense of Democracies (FDD), where she also contributes to FDD’s Center on Military and Political Power (CMPP). For more analysis from Andrea and CMPP, please subscribe HERE. Follow Andrea on Twitter @StrickerNonpro. Follow FDD on Twitter @FDD and @FDD_CMPP. FDD is a Washington, DC-based, nonpartisan research institute focusing on national security and foreign policy.