The chief of the U.N. nuclear agency is urging Iran to cooperate with a probe of his agency, in unusually frank language showing exasperation with the stalled investigation, according to a report of the Associated Press. Yukiya Amano of the International Atomic Energy Agency (IAEA) says negotiations with Iran to restart the probe "have been going around in circles." He says he is addressing his appeal "with a sense of urgency." Amano spoke Monday at the start of a 35-nation board meeting of his International Atomic Energy Agency. His comments were focused on Parchin, a nuclear site southeast of Tehran. The IAEA has tried vainly to get access to Parchin since early 2011.