World powers and Iran set new talks in nuclear dispute ALMATY (Reuters) - Six world powers ended two days of talks with Iran on its nuclear program without a breakthrough on Wednesday, but agreed to meet in Istanbul next month and resume negotiations in Kazakhstan on April 5. The six powers - France, Germany, the United States, China Russia and Britain - offered at the talks to lift some sanctions if Iran scaled back nuclear activity that the West fears could be used to build a bomb. Tehran, which denies seeking nuclear weapons, did not agree to do so and the sides did not appear any closer to an agreement to resolve a decade-old dispute that could lead to another war in the Middle East if diplomacy fails. But Iran said the talks were a positive step in which the six powers tried to "get closer to our viewpoint," and Western diplomats had set their sights low, making clear that an agreement to meet again soon would be deemed a success. In particular, they are aware that the closeness of Iran's presidential election in June is raising political tensions in Tehran and makes significant concessions unlikely. "I hope the Iranian side is looking positively on the proposal we put forward," said European Union foreign policy chief Catherine Ashton, who led the talks on behalf of the six powers. We have to see what happens next. Israel, assumed to be the only country in the Middle East with nuclear weapons, has hinted strongly that it could attack Iran's nuclear sites if diplomacy and sanctions do not stop its enrichment of uranium to near weapons-grade. One diplomat in Almaty said the Iranians appeared to be suggesting at the talks that they were opening new avenues, but that it was not clear if this was really the case. Both sides said experts would meet for talks in the Turkish city of Istanbul on March 18 and that political negotiators would return to Almaty on April 5-6. The meeting in the Kazakh city was the first between the world powers and Iran in eight months. Russian negotiator Sergei Ryabkov confirmed that the six powers had offered to ease sanctions on Iran if it stops enriching uranium to 20 percent fissile purity - a short technical step from weapons grade - at an underground site where it carries out its most controversial uranium enrichment work. Western officials said the offer of sanctions relief included a resumption of trade in gold and precious metals and lifting an embargo on imports of petrochemical products if Iran responded. But a U.S. official said the world powers had not offered to suspend oil or financial sanctions. The sanctions are hurting Iran's economy and its chief nuclear negotiator, Saeed Jalili, suggested Iran could discuss its production of nuclear fuel, although he appeared to rule out closing the underground enrichment plant at Fordow. In comments in Persian translated into English, Jalili told a news conference Fordow was under the supervision of the U.N. nuclear watchdog and there was no justification for closing it. Asked about the production of 20-percent enriched fuel, he reiterated Iran's position that it needed this for a research reactor and had a right to produce it. Iran says its enrichment program is aimed solely at producing nuclear energy so that it can export more oil, and that Israel's assumed nuclear arsenal is the main threat to peace in the region. But Jalili did indicate that Iran might be prepared to discuss the issue, saying: "This can be discussed in the negotiations ... in view of confidence building." Iran has also previously suggested that 20-percent enrichment was up for negotiation if it received the fuel from abroad instead. It also wants sanctions lifted. "While an agreement to meet again may not impress skeptics of diplomacy, an important development did occur," said Trita Parsi, an expert on Iran. The parties began searching for a solution by offering positive measures in order to secure concessions from the other side. In past meetings, the approach centered on coercion - the main motivator for concessions was the threat of new sanctions and other escalatory steps. Ali Vaez of the International Crisis group said the powers had broken a taboo by discussing sanctions relief. Another expert, Dina Esfandiary of the International Institute for Strategic Studies, said: "I note that the mood is more optimistic and that's great, but a deal still hasn't been reached and in my view its unlikely to be reached before the Iranian elections have come and gone." Additional reporting by Yeganeh Torbati in Almaty, Zahra Hosseinian in Zurich, Gabriela Baczynska in Moscow, Dan Williams in Jerusalem and Marcus George in Dubai; Writing by Timothy Heritage and Fredrik Dahl; Editing by Kevin Liffey