Foreign powers holding talks with Iran about its nuclear programme have said they are "disappointed" little progress has been made in Istanbul. Two days of talks between six world powers and Iran, aimed at persuading Tehran to rein in its nuclear programme, have concluded with no agreement. Iran tried to impose preconditions on any deal, said the EU foreign policy chief, Lady Catherine Ashton. Ashton, who led an international delegation at the talks, said Iran had insisted the UN Security Council lift sanctions imposed because of its refusal to stop uranium enrichment. Iran was also seeking recognition by the six countries that it had a right to enrich. Ashton, who led representatives from the US, Britain, France, Russia, China and Germany, said no new talks had been scheduled but the "door remains open". Her Iranian counterpart, Saeed Jalili, is expected to hold a news conference on the outcome of the talks.