Iran and six world powers have agreed to meet in Turkey in late January 2011 after two days of talks in Geneva on Tehran's disputed nuclear programme.
European Union foreign policy chief Catherine Ashton said the Geneva talks were "detailed and substantive" but said Iran must “comply with international obligations". Iran says it will not discuss stopping uranium enrichment.
The talks in Geneva involved Iran's top nuclear negotiator, Saeed Jalili, along with Ashton and senior officials from the five permanent members of the United Nations Security Council - the United States, Russia, China, France and Britain - plus Germany.
Ashton told reporters: "We and Iran agreed to a continuation of these talks in late January in Istanbul where we plan to discuss practical ideas and ways of cooperating towards resolution of our core concerns about the nuclear issue."
In Geneva the powers tried to put pressure on Iran to agree to discuss its nuclear work, which the West suspects is aimed at making bombs.
Iran, however, declared it would not back down.
"We will not talk about Iran's nuclear rights and Iran will never accept pressure," Jalili told Iranian state television.
"I am announcing openly and clearly that Iran will not discuss a uranium enrichment halt in the next meeting in Istanbul with major powers," Jalili told a news conference in Geneva.
Iranian President Mahmoud Ahmadinejad warned that unless they lift UN sanctions the six face failure in the next round.
swissinfo.ch and agencies