(Reuters) - Iran and major powers agreed on Tuesday to meet again next month in their dispute over Tehran´s nuclear program, but the chief Iranian negotiator said there could be no discussion of any halt to uranium enrichment.

The agreement to reconvene in Turkey in late January, after two days of talks in Geneva this week, was as much as either side had expected from their first meeting in over a year on the intractable nuclear issue.

Iran has insisted all along that it has the right to enrich uranium for peaceful electricity generation and will never give into pressure and abandon that right.

Iran had also said it would not discuss enrichment in Geneva, but Western diplomats said a range of issues including the nuclear dispute were tackled at this week´s talks.

"I am announcing openly and clearly that Iran will not discuss a uranium enrichment halt in the next meeting in Istanbul with major powers," chief Iranian negotiator Saeed Jalili told a news conference.

Iran rejects Western suspicions that its nuclear program is a cover for acquiring an atomic bomb.

The enrichment issue remains the major obstacle to resolving a dispute which has the potential to ignite a major conflict in the Middle East. Enriched uranium can be used both in power stations and, when refined to a much higher degree, in nuclear bombs.

Repeated U.N. Security Council resolutions demand Iran suspend enrichment and allow tougher U.N. inspections of its atomic work as a way of convincing the world it is not secretly trying to develop a nuclear weapons capability.

That demand remains the position of the six powers, a senior U.S. administration official said in Geneva after the talks which he described as "difficult and candid."

The U.S. official, who asked not to be named, said the United States did not have a formal bilateral meeting with Iran, but had had opportunities to communicate its main points.

"We had several informal interactions which were useful to reinforce our main concerns," the official told reporters.

CONFIDENCE-BUILDING

A revised version of a nuclear fuel swap, agreed and then later rejected by Iran last year, could be a way to build confidence between the two sides, the official said.

But analysts say Iran´s hardline leaders, who use the nuclear program to rally nationalist support and distract from domestic problems, are unlikely ever to agree to back down on the main issue of enrichment.

"This government has obviously linked the development of the nuclear program so closely to its own legitimacy that it would be difficult for them to backtrack on it," said Gala Riani of the IHS Global Insight consultancy.

EU foreign policy chief Catherine Ashton, representing the six powers -- the United States, Russia, China, Britain, France and Germany -- told a news conference: "We and Iran agreed to a continuation of these talks in late January in Istanbul where we plan to discuss practical ideas and ways of cooperating toward resolution of our core concerns about the nuclear issue."

Jalili said that was the only thing agreed in Geneva.

"I hope the other party remains committed to our agreement at the meeting ... as long as they remain committed then the talks can go ahead," Jalili said.

Tehran would not negotiate under pressure, he said.

"I wouldn´t describe the talks we´ve had today as fruitful, but it´s a start," said an EU official. "A problem like this is not going to be solved in two days; it´s not an easy problem."

"Given the history you can´t be optimistic, but there´s no point in doing these things with the objective of failure," the official said. "The problem is that the level of trust is about as low as it could get anywhere outside of North Korea."

In a speech in Iran, President Mahmoud Ahmadinejad called on the powers to publicly declare Iran´s national "rights," saying they would have "nothing but remorse" if they failed to do so.

Iran, which announced a breakthrough in its nuclear technology on the eve of the talks, has been under increasing pressure from sanctions imposed by the West.

It dismisses the impact of such penalties, saying trade and other sanctions imposed since the 1979 Islamic revolution that toppled the U.S.-backed shah have made the country stronger.

(Additional reporting by Ramin Mostafavi and Robin Pomeroy in Tehran, Stephanie Nebehay in Geneva and Fredrik Dahl in Vienna; Writing by Jonathan Lynn and Jon Hemming; Editing Mark Trevelyan) (© Reuters 2010 12/07/10)