(AGI) Vienna, July 12 - On the eve of the resumption of talkson the controversial Iranian nuclear programme to take place inVienna on Sunday, U.S. delegation sources defined Iran's stanceas 'inadequate and unfeasible'. The news was released by one ofthe U.S. delegation members attending the talks between Iranand the 5+1 group, underlining that there are still many verydifferent opinions on several issues, beginning with uraniumenrichment. The United States, therefore, does not believe thatthe negotiations can be further extended beyond the July 20deadline (date by which a final agreement should be reached)without Iran making 'significant progress on the key issues'. . .