Iran and its European negotiating partners struggled without success on Wednesday to break an impasse on reaching a long-term agreement on nuclear, economic and security cooperation.
But the Iranian side presented new proposals to provide further assurances to the Europeans that Iran's nuclear program is peaceful and the two sides have agreed to meet again soon, participants said.
"We had rather extensive talks, and we presented a number of ideas on how we can move forward," M. Javad Zarif, ambassador to the UN and the leader of the delegation, said in a telephone interview.
A European who took part in the meeting said, "By the standards of international group bureaucracies and negotiations, we've moved forward a bit."
Senior negotiators from Iran on one side and France, Germany, Britain and the EU on the other met at the French Foreign Ministry to review three months of negotiations aimed at providing objective proof that Iran's nuclear program is not designed to produce nuclear weapons.
Among the ideas presented by the Iranians, participants said, was a phased approach including enhanced monitoring and technical guarantees devised to allow Iran to again enrich uranium, a process used in producing nuclear energy and nuclear bombs. But the Europeans reject that approach, arguing that Iran's nuclear activities are so suspicious that it should never again be allowed to enrich uranium.
Sirus Naseri, a senior Iranian negotiator, told reporters after the talks on Wednesday that Iran would not give in to the European demand that it give up delicate nuclear activities.
"This is not something we are prepared to consider," he said. He reiterated the Iranian demand that concrete progress must be made soon.
"Time is of the essence," he said.
A European participant said, "We are no further forward on this issue."
The meeting on Wednesday was the first by the negotiating teams since the Bush administration softened its position to allow the Europeans to offer broader economic incentives to Iran. In exchange, the US has extracted a pledge from the Europeans to refer Iran's case to the UN for possible censure or penalties, if the negotiations fail.
The Europeans laid out the difficulties in the talks on March 10 in a confidential, four-page status report that acknowledged that "progress is not as fast as we would wish."
But the report added that recent international support for the European negotiating process, particularly from the United States and Russia, "has strengthened the prospects for a satisfactory outcome."
The report said that the Europeans were proposing that Iran acquire a light-water research reactor to replace a planned heavy-water research reactor, which is designed to produce plutonium that could be used to fuel weapons.
According to weapons specialists, plutonium is often preferred to enriched uranium for compact warheads on missiles because it takes less to produce a significant blast. Light-water reactors are considered better for producing electricity than plutonium.
The Europeans are considering dispatching teams of specialists to Iran to investigate the possibility of providing it with such a reactor, a European negotiator said. That plan would ultimately require American support because some of the technologies needed are barred by US restrictions.