Iran has ruled out freezing its nuclear program in Saturday's international talks that included the United States for the first time.

But the Islamic Republic has agreed to resume talks on suspending uranium enrichment with European Union's chief negotiators in two weeks.

EU envoy Javier Solana told reporters after the Geneva talks with Iranian negotiator Saeed Jalili that the two would speak either by telephone or personally.

"I think in general terms constructive, but as I have said before, I have not been, the reply to the answer I was looking for has not come clearly."

Jalili said Tehran would remain constructive, but asked that Western powers not turn away from negotiations.

"In our proposed package we have included a number of possible constructive points of cooperation, which are designed to address our common concerns."

Saturday's meeting was led by Javier Solana and attended by senior diplomats from the United States, Russia, China, Britain, France and Germany.

Representing China at the Geneva talks is Chinese Assistant Foreign Minister Liu Jieyi.

"Currently there is a rare opportunity for promoting the resumption of negotionations on the Iranian nuclear issue. Enhanced diplomatic efforts and flexibility are needed for an early resumption of the negotiations so that a long term, comprehensive and appropriate solution could be found for the nuclear issue."

US Undersecretary of State William Burns was also present, but did not speak publicly.

The US participation was seen as a shift of long-standing U.S. policy toward Iran.

Washington had always insisted that it would not talk with Tehran unless it halts its uranium enrichment activities.