Iran and six world powers ended two days of nuclear talks in Istanbul without significant progress, Catherine Ashton, the negotiator for the so-called 5+1 group, said Saturday, DPA reported.
"We had hoped to embark on a discussion of practical ways forward. I'm disappointed to say that this was not possible," Ashton said at a press conference following the talks.
Ashton said the 5+1 group, comprised of the five permanent members of the United Nations Security Council - United States, Britain, France, Russia and China - plus Germany, had presented Iran with "specific practical proposals" for building trust but Iran did not accept them.
The proposals included an updated nuclear swap deal and ways for Iran to improve transparency in its dealings with the International Atomic Energy Agency (IAEA).
While expressing disappointment at the lack of concrete progress, Ashton emphasized that "the door remains open" for Iran to respond to the group's proposals. She said no further talks between Iran and the six powers had been planned.
Prior to talks, both sides had expressed tentative hopes for a nuclear swap deal, in which Iranian low-enriched uranium (LEU) would be exchanged in return for foreign-made fuel for a Tehran research reactor.
The so-called Vienna Group, comprised of the United States, Russia, France, Iran and the International Atomic Energy Agency (IAEA), which was formed after the October 2009 nuclear talks in Geneva to carry out a nuclear swap, met on the sidelines of the Istanbul meetings to discuss a swap deal but did not reach an agreement.
Iran insists its nuclear programme is for peaceful purposes, but many countries fear it is aimed at developing nuclear weapons.
Alleging a lack of transparency by Tehran about some aspects of its nuclear programme, the UN Security Council is demanding that Iran stop all nuclear enrichment. Tehran has steadfastly rejected the demand.