The International Atomic Energy Agency Director General Rafael Grossi said on Monday that the agency had detected residues of uranium at a location in Iran, undeclared by the local authorities. "The presence of multiple uranium particles of anthropogenic origin, including isotopically altered particles, at a location which was not declared by Iran, is a clear indication that nuclear material and/or equipment contaminated by nuclear material has been present at this location," Grossi disclosed in his address to a virtual session of the IAEA Board of Directors. Grossi continued, saying, "After 18 months, Iran has not provided the necessary, full and technically credible explanation for the presence of these particles. "In the absence of a technically credible explanation from Iran, the agency is deeply concerned that undeclared nuclear material may have been present at this undeclared location and that such nuclear material remains unreported by Iran under its Safeguards Agreement." With regard to three other locations, none of which was declared to the agency, Iran has not answered any of the agency's questions relating to the possible presence at these locations of nuclear material. Results of environmental samples taken in 2020 at two of these locations found particles of anthropogenic uranium. Last month, "we conveyed our results and related questions to Iran." "During my trip to Tehran on Feb. 20-21, I stressed to the government of Iran my concern at the lack of progress in clarifying the safeguards issues relating to the four locations mentioned. "I expressed my readiness to engage Iran in a proactive and focused effort to break the impasse, and to clarify and resolve these issues without further delay. "Since my previous quarterly report, I have issued 11 reports containing updates on those activities. These reflect a number of notable developments related to Iran's program over the past few months." On Feb. 15, Iran informed the agency that Iran would "stop the implementation of voluntary transparency measures as envisaged in the JCPOA, as of Feb. 23, 2021," including the provisions of the Additional Protocol and Modified code 3.1 of the subsidiary arrangements to Iran's Safeguards Agreement, Grossi elaborated. "I had already informed that stopping or limiting the agency's verification and monitoring activities at this stage would have a serious impact on the agency's ability to report on the implementation of Iran's commitments," he added. Grossi noted that on Feb. 21, he held talks with Iranian officials in Tehran to try find "a mutually agreeable solution for the agency to continue essential verification activities. As it has been announced, we were able to reach a temporary bilateral technical understanding." — KUNA