Iran nuclear: Geneva talks 'something to build on'
Talks between world powers and Iran have failed to reach an agreement on Tehran's nuclear programme.
EU foreign policy chief Catherine Ashton told a press conference that there had been a lot of "concrete progress but some differences remain".
Baroness Ashton said talks would resume on 20 November.
Iranian Foreign Minister Mohammad Javad Zarif said he was not disappointed with the outcome in Geneva, and that the talks were "something we can build on".
He said all parties were "on the same wavelength" and "there was the impetus to reach an agreement".
US Secretary of State John Kerry said: "There is no question in my mind that we are closer now than we were before."
The international powers are concerned that Tehran is trying to build a nuclear weapon - but Iran says its programme is peaceful.
A proposal that was floated would require Iran to freeze expansion of nuclear activity in return for limited relief from economic sanctions.
Iranian President Hassan Rouhani said on Sunday that his country would not abandon its "nuclear rights", which included uranium enrichment.
"The rights of the Iranian nation and our national interests are a red line. So are nuclear rights under the framework of international regulations, which include enrichment on Iranian soil," he told parliament in remarks quoted by the Isna news agency.
Delegates had earlier suggested there was "good progress".
But diplomatic sources said France had wanted tougher terms for Iran.
Before the late-night press conference, French Foreign Minister Laurent Fabius said the three days of negotiations had ended without a deal.
"The meetings in Geneva have made it possible to move forward," he said.
"But we have not yet managed to conclude, because there are still some questions remaining to be dealt with."
Meanwhile, Mr Kerry told reporters: "We have not only narrowed differences and clarified those that remain but we made significant progress in working through the approaches to this question of how one reins in a programme and guarantees its peaceful nature."
He added that the window for diplomacy would not stay open indefinitely.
The Geneva talks involve Iran and the P5+1 - the US, Russia, Britain, France and China as permanent UN Security Council members, plus Germany.