The six states — the United States, Russia, China, Britain, France and Germany, coordinated by the European Union — sought the talks to address Iran’s uranium enrichment drive, while Tehran sought to broaden the agenda to global security issues.
“Talks have adjourned for the evening and will resume tomorrow,” said the official, who asked not to be named.
Other officials attending the Geneva talks said European foreign policy chief Catherine Ashton would meet Iran’s top nuclear negotiator Saeed Jalili over dinner on Monday for further discussions.
Iranian officials at the talks said they were held in a “positive and constructive atmosphere”, according to Iranian state television.
Officials declined to say whether a series of bilateral contacts between the powers and Iran during the afternoon included one with the United States, which has had no diplomatic relations with Tehran since its 1979 Islamic Revolution.
The six powers played down expectations of dramatic results from the talks, but hope that they will lead to further negotiations on Iran’s nuclear energy ambitions, which the West suspect entail developing the means to build atomic bombs.
Consultations are already under way on a date for further talks, a European official said.
Tehran says it is enriching uranium only for electricity purposes so it can export more of its bountiful oil.
Iranian President Mahmoud Ahmadinejad said last week the topic of uranium enrichment was not on the agenda at Geneva.
But the western official said the question was raised by each of the six powers at talks during the morning. It was not immediately known whether Iranian officials addressed the enrichment issue in response.
Following last week’s killing of an Iranian nuclear scientist in Tehran, Iran raised the question of assassinations and Ashton condemned them, the Western official said.
On the eve of the meeting in Geneva, Iran announced what it called a major step forward in its nuclear work, signalling it is not about to back down in the long-running battle over what it insists are peaceful plans for energy production.
