March 22: Western intelligence agencies have concluded that Iran is hiding aspects of its nuclear program, including machinery, pumps, spare parts for centrifuges, and carbon fiber—a key component for producing advanced centrifuges—from the International Atomic Energy Agency (IAEA). According to intelligence officials, the material and equipment is concealed in 75 containers spread across locations under the control of the Islamic Revolutionary Guard Corps (IRGC) and the Atomic Energy Organization of Iran (AEOI). These containers regularly move between sites administered by the AEOI or the IRGC, with most of the containers recently moved from the AEOI's Uranium Conversion Facility in Isfahan to IRGC-controlled sites. Iran must declare certain equipment and material relevant to its nuclear program to the IAEA under the terms of the Joint Comprehensive Plan of Action (JCPOA). The intelligence agencies believe that Iran possessed some of the undeclared equipment before the 2015 accord took effect, but obtained other components on the black market afterwards.