Western powers pressed Iran on Wednesday to tackle suspicions that it may have worked on designing an atomic bomb and the United States said the issue would be central to the success of talks on a final settlement over Tehran’s nuclear programme. At a board meeting of the International Atomic Energy Agency, Washington and the European Union underlined their support for the U.N. watchdog’s efforts to investigate long-running allegations of possible nuclear arms research by Iran. The IAEA inquiry is separate from but complementary to higher-level political talks between Iran and six world powers aimed at a deal on the overall scope of Tehran’s nuclear energy programme to ensure it cannot be diverted into bomb-making. Western officials at the closed-door session of the IAEA’s 35-nation governing board in Vienna made clear the Islamic Republic must do much more. The U.S. ambassador to the IAEA, Joseph Macmanus, said it remained critical for Iran to address substantively all international concerns about the so-called possible military dimensions (PMD) of the country’s nuclear programme. A “satisfactory resolution of PMD issues will be critical to any long-term comprehensive solution to the Iranian nuclear issue,” Macmanus said, according to a copy of his statement. He later told reporters: “It is a central element to this negotiation, and all parties recognise that.” The 28-nation European Union voiced a similar line in its statement: “We urge Iran to cooperate fully with the agency regarding PMD issues, and to provide the agency with access to all people, documents and sites requested.”