Catherine Ashton, the European Union's foreign-policy chief, has described two days of talks between world powers and Iran on Tehran's disputed nuclear program as "detailed" and "substantive."
Ashton also confirmed that negotiations would resume in Istanbul in late January.
"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 a resolution of our core concerns about the nuclear issue," Ashton said.
Iran's chief negotiator, Said Jalili, made clear that halting uranium enrichment will not be discussed at the Istanbul meeting.
The Geneva talks brought together Iran and the five permanent UN Security Council members -- Britain, China, France, Russia and the United States -- and Germany.
The UN Security Council has imposed four rounds of sanctions on Iran over its refusal to halt uranium-enrichment activities. Enriched uranium can be used in nuclear reactors or nuclear weapons.
Iran denies any intention to make nuclear weapons and insists it has a "right" to a nuclear fuel cycle.
Earlier in the day, President Mahmud Ahmadinejad was quoted as saying talks with world powers would be "fruitful"
if sanctions imposed on Iran over its nuclear program were scrapped.compiled from agency reports