WESTERN powers have again pressed Iran to tackle suspicions it may have worked on designing an atomic bomb as the US 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 EU underlined their support for the UN 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 bombmaking.

The IAEA's 35-nation governing board in Vienna made clear the Islamic Republic must do much more to address concerns about its nuclear programme.

Iran denies claims it trying to make atomic ­weapons, saying its nuclear programme is to produce electricity.