ISTANBUL (AP) - Nuclear negotiators for Iran and six world powers were making encouraging progress in bridging differences that have doomed previous meetings meant to reduce fears over Tehran's atomic program, diplomats close to the talks said.
With the meeting just breaking for lunch, the diplomats cautioned against premature optimism about the outcome. But they said the unfolding dialogue between the two sides suggested they would find enough common ground for a second round in several weeks' time.
Iran is under four sets of U.N. sanctions for refusing to stop uranium enrichment - which can be used both to make reactor fuel and the fissile core of nuclear warheads - and the international community continues to demand that Tehran stop the activity.
But the last set of nuclear talks broke up without result more than 14 months ago after the Iranian team had refused to even discuss enrichment. The six, thus had come to Saturday's meeting with more modest expectations. Diplomats said before the meeting began that even general Iranian readiness to accept the need to discuss its enrichment program would be considered enough of a success to warrant a follow-up round.
One of the diplomats, who demanded anonymity because he was sharing information from a closed session, said the Iranians appeared to be moving toward that goal, engaging in discussion about the peaceful use of nuclear energy and the Nuclear Nonproliferation Treaty.
He said the Iranian team had mentioned supreme leader Ayatollah Ali Khamenei's "fatwa," or prohibition, of nuclear weapons for Iran, in the course of the plenary discussions. After lunch the meeting would go into bilateral sessions, he said - a setup that will be closely watched to see if the Americans meet directly with the Iranians.
Such encounters are rare and would indicate a further thaw in tensions at the talks.
"I would say there was a very constructive atmosphere compared to last time ... generally a positive vibe," he said. "The principle seems to be there for future negotiations."
Another diplomat described the just-completed session as a "useful morning's work," saying the Iranians appeared to be looking for a "serious process" at the talks. He too demanded anonymity because his information was privileged.
Iran insists it has no nuclear weapons ambitions, but the international community fears it could use its uranium enrichment program not only to make reactor fuel but also the fissile core of nuclear weapons.
Ahead of the meeting, European Union Foreign Policy Chief Catherine Ashton, who is the facilitator for the six nations engaging Iran, expressed hope that it will be "the beginnings of a sustained process," in a statement whose language reflected the meeting's main goal - establishing enough trust to keep the process going.
"What we are here to do is to find ways in which we can build confidence between us and ways in which we can demonstrate that Iran is moving away from a nuclear weapons program."
For his part, chief Iranian negotiator Saeed Jalili said the talks "will serve the dignity of the Iranian nation, as he walking into the talks Saturday at one of Istanbul main conference venues overlooking the Bosphorus.
Officially, the international community's long-term goal remains what it was when nuclear negotiations began eight years ago - persuading Tehran to stop all uranium enrichment and thereby relieve fears that it will use that program to create the fissile core of nuclear warheads. Tehran has long denied any weapons-related nuclear goals.
A senior diplomat involved in the talks said however, that influential Western nations now are increasingly agreed that Iran should be allowed to keep some enrichment activity "under the right circumstances" - sometime in the future, if all fears about possible Iranian plans to make nuclear weapons are put to rest. He demanded anonymity because his information was confidential.
The West's strongest bargaining chip is linked to its sanctions on Iran, penalties that have been tightened in recent months as the U.S. and EU have taken aim at Iran's main cash cow: oil. At the talks, it may specifically probe whether Tehran is ready to halting uranium enrichment at a level higher than it needs to make reactor fuel because higher-level material can be turned more quickly into warhead material.
Iranian officials have suggested scaling back on uranium enrichment while continuing to make nuclear fuel and ahead of the talks, Jalili, the chief Iranian nuclear negotiator, vowed to present new initiatives, without specifying what they might be.
"There have been signals that suggest to us they are more serious than the last time," said Ashton spokesman Michael noting that Jalili's letter to Ashton setting up the talks indicated Iran now was ready to talk about its enrichment program.
Preliminary encounters between the two sides reflected the relatively positive atmosphere unfolding at the talks, in an Istanbul conference center overlooking the Bosphorus.
Ashton and Jalili met for more than three hours over dinner Friday evening, in what participants who demanded anonymity because they were relaying confidential information said was a relaxed atmosphere.
They said discussions did not focus on nuclear issues. A member of the Iranian delegation told The Associated Press that when Jalili was reminded that the dinner had been planned for a shorter period, he replied, "we need to continue."