More discussions in Baghdad on May 23ISTANBUL — Iranian and European officials expressed confidence in the results of Saturday's negotiations on Tehran's disputed nuclear program as it was announced that the two sides will meet again in Baghdad on May 23. The very fact that there will be another round adds to a growing sense among diplomats that the two sides were making notable progress in talks that have grown increasingly tense as the West has tightened sanctions on Iran and Israel has threatened a preemptive military strike on the Islamic republic. But the challenges in the next round could be far more significant. That's when the six powers will likely seek further commitments from Tehran to reduce concerns that it could use its uranium enrichment program to make the fissile core of nuclear missiles. EU foreign policy chief Catherine Ashton called the talks in Istanbul constructive and said future talks will be guided by the “principle of a step-by-step approach and reciprocity.” That indicates the international community is ready to reward Iran if it moves to alleviate fears that it intends to weaponize its nuclear program — rewards that could include delaying or easing some sanctions. Iran's chief negotiator, Saeed Jalili, said his team “saw a positive approach (from the other side) and we consider it a step forward.” Iran insists its nuclear program is peaceful, and Ashton said Saturday that Tehran has a right to such a peaceful program. At the same time, she added, the Nuclear Nonproliferation Treaty must be the “key basis” for future talks. Iran asserts that it has not violated the treaty, and that it has a right under that agreement to enrich uranium for peaceful purposes. Asked about the making the treat the basis of the talks, Jalili said, “We expect that we should enjoy our rights in parallel with our obligations.” Iran is under four sets of UN 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 global 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 refused to even discuss enrichment. 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.