By Yeganeh Torbati and Justyna Pawlak
ALMATY (Reuters) - Iran's chief nuclear negotiator Saeed Jalili sounded a defiant note ahead of a new round of talks with world powers in Kazakhstan, saying on Thursday they had to recognize Iran's right to enrich uranium to see any breakthrough.
The six powers - United States, Russia, China, France, Britain and Germany - will meet Iranian negotiators on Friday and Saturday in the Kazakh city of Almaty, hoping Tehran agrees to scale back its most sensitive atomic work that they suspect is aimed at achieving a nuclear weapons capability.
Iran has refused to do so during a decade of on-and-off negotiations, despite hardening economic sanctions, arguing its uranium enrichment has peaceful purposes only and therefore can continue under international law.
Jalili, speaking at a university in Almaty, said that stance would not change.
"We think our talks tomorrow can go forward with one word. That is the acceptance of the rights of Iran, particularly the right to enrichment," he said.
World powers argue Iran has given up its right to enrich uranium under international rules because it has hidden nuclear work from United Nations inspectors in the past and has refused to open fully to their investigations.
Jalili said Iran would continue to defend its policy regardless of a June presidential election, which Western diplomats say complicates Tehran's approach to talks.
"The impact of the election will be that ... our people will defend their right with more rigor," Jalili said.
There is broad unity within the Iranian political establishment on pursuing the nuclear program and policy on the issue is closely overseen by Ayatollah Ali Khamenei, Iran's supreme leader who has the last word on all momentous matters.
In Almaty, their second meeting with Iran in Kazakhstan's commercial center in five weeks, the powers want Iran to agree to suspend higher-grade uranium production in return for modest relief from economic sanctions.
Stakes are high in the negotiations. Israel, widely assumed to be the Middle East's only nuclear power, has said it would bomb Iran's military installations if diplomacy and sanctions fail to curb nuclear progress.
That could in turn spark reprisals by Iran and its regional allies, engulfing the Middle East in a new war. Oil prices could jump and threaten the fragile global economy.
At the core of the international community's concerns are Iran's efforts to enrich uranium to 20 percent fissile purity, a level that closes an important technological gap en route to making weapons-grade material.
During the last meeting in Almaty in February world powers told Iran to stop producing such uranium and constrain the ability to quickly resume operations at the Fordow facility, buried deep in a mountain near the Iranian city of Qom.
The EU's foreign policy chief Catherine Ashton said during a trip to Turkey on Wednesday that she was "cautiously optimistic" about prospects of a deal in Almaty.
"But I am also very clear that it is very important that we do get a response (from Iran)," she told reporters.
Iranian media quoted deputy negotiator Ali Bagheri as saying in Almaty that Tehran would suggest its own deal at talks.
"Iran will enter tomorrow's negotiations with clear and instrumental proposals," he was quoted saying.
Russia's foreign ministry spokesman voiced skepticism on Thursday, saying there were scant signs of progress so far.
"The sides in the negotiations process unfortunately have not yet begun to move toward working out compromise agreements," Alexander Lukashevich told reporters in Moscow.