Vienna: Western powers told Iran on Thursday it must step up cooperation with a U.N. watchdog investigation into suspected atomic bomb research if it wants to get a broader nuclear deal that would ease sanctions on the oil producer.
The United States and the European Union said they were concerned about the slow headway so far in the U.N. atomic agency`s long-running inquiry into allegations that Iran has worked on designing a nuclear weapon. Iran denies the charge.
A report by the U.N.`s International Atomic Energy Agency in early September showed Iran had failed to answer questions about what the IAEA calls the possible military dimensions of the country`s nuclear programme by an Aug. 25 deadline.
The EU said it was disappointed with the "very limited progress" in that investigation in a statement at a quarterly meeting of the IAEA`s board of governors.
"The EU underlines that resolving all outstanding issues (between Iran and the IAEA) will be essential to achieve a comprehensive, negotiated long-term settlement," it added.
Six global powers - the United States, Russia, China, Britain, France and Germany - are trying to negotiate a resolution to a wider, decade-old dispute with Iran over its atomic activities.
Those talks resume in New York this week, but a quick diplomatic breakthrough is seen as unlikely.
Analysts say a stalled IAEA inquiry could further complicate the powers` parallel efforts to reach a settlement with Iran on curbing its nuclear programme in exchange for a gradual phasing out of sanctions hurting its economy.
U.S. envoy Laura Kennedy echoed the EU`s message, telling reporters outside the IAEA meeting: "We do remain concerned ... about the pace of progress in addressing the possible military dimensions of Iran`s nuclear programme."
Iran has been promising to cooperate with the IAEA since Hassan Rouhani, seen as a pragmatist, was elected president last year. It says its nuclear programme is for purely non-military purposes.
But Iran did not address two key issues by late August as agreed with the IAEA: alleged experiments on explosives that could be used for an atomic device, and studies related to calculating nuclear explosive yields.
They were part of a landmark report published by the IAEA in 2011 with intelligence indicating Iran had a nuclear weapons research programme but halted it in 2003 when it came under increased international pressure. The intelligence suggested some activities may have resumed later. The report identified about 12 specific areas that it said needed clarification.
Iran says the allegations are baseless.
"We urge Iran to intensify its engagement with the agency," Kennedy, the U.S. envoy, said. "Concerns about the possible military dimensions of Iran`s nuclear programme must be addressed as part of any comprehensive solution."
"Only when this happens will it be possible to have confidence that Iran`s nuclear programme is and will remain exclusively peaceful," she said.
Rouhani`s election raised hopes of a solution to the stand-off with the West after years of tension and fears of a new Middle East war. An interim accord was reached between Iran and the six powers in Geneva in November last year.
But they did not meet a self-imposed July target date for a long-term accord and now face a new deadline of Nov. 24.
While the powers seek to limit the size of Iran`s future nuclear programme - and thereby extend the time it would need for any bid to amass fissile material for a weapon - the IAEA is investigating alleged research and experiments in the past that could be used to make the bomb itself.
Western officials say that although there is no chance of the IAEA inquiry being completed before the scheduled end of the six-power talks, some of the sanctions relief Iran is seeking would probably depend on its cooperation with the U.N. agency.