Nuclear talks with Iran were proceeding ´positively,´ said a spokesman for European Union foreign policy chief Catherine Ashton on Saturday, who is heading the Western delegation at talks over Tehran´s nuclear program in Istanbul.

World powers and Iran launched the new round of negotiations in Istanbul on Saturday, aiming to resolve a long-standing dispute over Tehran´s nuclear program that threatens to spark a new war in the Middle East.

Nuclear talks with Iran were proceeding ´positively,´ said a spokesman for European Union foreign policy chief Catherine Ashton on Saturday, who is heading the Western delegation at talks over Tehran´s nuclear program in Istanbul.

World powers and Iran launched the new round of negotiations in Istanbul on Saturday, aiming to resolve a long-standing dispute over Tehran´s nuclear program that threatens to spark a new war in the Middle East.

Iran´s top national security official Saeed Jalili (R) poses with European Union´s Foreign Policy chief Catherine Ashton before a meeting on April 14, 2012.

Photo by: AFP Ashton´s spokesman Michael Mann said the first two-and-a-half-hour session had been conducted in a "constructive" and "positive" manner.

The talks would reconvene with bilateral meetings after a 90-minute lunchbreak, he said. Mann, who earlier told dpa that no major breakthrough was expected in Istanbul, declined to give details of the bilaterals.

One diplomat close to the talks said that 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.

The diplomat cautioned against premature optimism about the outcome, but 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 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 international community continues to demand that Tehran stop the activity.

The diplomat, 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.

"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."

A source close to the Iranian delegation in Istanbul told dpa on Saturday that Iran has proposed to swap its enriched uranium for foreign-made nuclear fuel rods, to be used in civilian nuclear power plants.

In an apparent attempt to revive a previous plan that has fallen through, Iran would ship out uranium enriched to 3.5 per cent, and Russia and France would turn it into fuel.

In addition, Iran has proposed to turn the uranium it has enriched to a higher level of 20 per cent into fuel itself under the supervision of the International Atomic Energy Agency, the source said.

Meanwhile the official Iranian news agency IRNA reported on Saturday that Iran had rejected a request by the U.S. envoy or a meeting with Iran´s chief nuclear negotiator during the talks in Istanbul.

Ahead of the meeting, Ashton, expressed hope that it will be "the beginnings of a sustained process," in a statement whose language reflected the meeting´s main goal, to establish enough trust to keep the process going.

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 at one of Istanbul main conference venues overlooking the Bosphorus on Saturday. (© Copyright 2012 Ha´aretz 04/15/12)