VIENNA — Iran faced Western pressure on Wednesday to speed up its promised cooperation with a long-stalled UN nuclear watchdog investigation into suspected atomic bomb research by Tehran, something the Islamic state denies. The European Union — which groups three of the six powers seeking to negotiate a settlement to a decade-old dispute with Iran over its nuclear program — noted that "some" progress had been made in separate talks between Iran and the International Atomic Energy Agency (IAEA). But, the 28-nation EU added in a statement to a quarterly meeting of the IAEA's 35-nation governing board, "We call on Iran to provide all the relevant information to the agency, to address fully the substance of all of the concerns and to accelerate its cooperation with the agency." Canada's ambassador to the Vienna-based IAEA put it more bluntly, saying Iran was using a kind of "salami-sliced, piece-by-piece approach" in its dealings with the UN watchdog. "We are definitely of the view that Iran is moving too slowly to address these long-standing questions. They do need to move faster," Mark Bailey told Reuters. For several years, the IAEA has been investigating suspicions that Iran may have coordinated efforts to process uranium, test explosives and revamp a ballistic missile cone in a way suitable for a nuclear warhead. Iran says the allegations are false but has offered to help clarify them. Tehran says its uranium enrichment program is a peaceful energy project whereas the West fears it is covertly oriented to develop nuclear weapons capability. Western diplomats have long accused Tehran of stonewalling the IAEA's probe. After years of increasing tension with the West, last June's election of Hassan Rohani as Iranian president paved the way for a dramatic thaw in relations. However, the sides remain far apart on what a long-term nuclear agreement should look like. US officials say it is vital for Iran to resolve the IAEA's questions if the US, France, Germany, Britain, China and Russia are to reach a long-term accord with Iran that would set a verifiable framework for its nuclear activity and end punitive international sanctions imposed on Tehran. — Reuters