VIENNA (Reuters) - An Iranian envoy voiced hope on Monday that talks with the U.N. nuclear watchdog in mid-May would help resolve "outstanding issues", but he again ruled out any halt to the Islamic state's controversial uranium enrichment programme.
The International Atomic Energy Agency (IAEA) said on Saturday it would resume discussions with Iran on May 14-15 - more than two months after their last meeting over concerns about Tehran's atomic activities ended in failure.
"We hope that this will be a very constructive and successful meeting," Iran's ambassador to the Vienna-based IAEA, Ali Asghar Soltanieh, told Reuters.
"The main purpose is to negotiate on a modality and framework to resolve outstanding issues and remove ambiguities," he added, echoing language he and other Iranian officials have used before previous meetings that yielded no notable progress.
He suggested that only after such a "framework" for future cooperation had been agreed could Iran consider an IAEA request for access to a military site where the U.N. agency believes nuclear-related weapons research may have taken place.
"Every action will be implemented based on this framework, afterward," Soltanieh said when asked whether the IAEA could visit Parchin southeast of the capital Tehran.
Western diplomats, who suspect Iran may be "sanitizing" Parchin ahead of any visit, have said Tehran still appears to be stonewalling over the U.N. body's most pressing demand to let its inspectors travel to the site.
The IAEA last November issued a report detailing alleged Iranian research and development activities that were relevant to manufacturing nuclear weapons, lending independent weight to Western suspicions based on intelligence findings.
The IAEA wants Iran to address the questions raised in the report about possible military dimensions to Tehran's uranium enrichment programme. Iran has dismissed Western allegations as fabricated and baseless.
"The agency will continue to address the Iran nuclear issue through dialogue and in a constructive spirit, with a view to resolving all outstanding issues," IAEA Assistant Director General Rafael Grossi said in a speech on Monday.
Iran has also restarted negotiations with six world powers over the broader dimensions of its enrichment programme and the sides have agreed to meet again in Baghdad on May 23.
Iranian Foreign Minister Ali Akbar Salehi said last week that he was optimistic that the talks with United States, Russia, China, Germany, France and Britain would make progress.
Washington and its allies believe Tehran is working on developing nuclear bomb capability. Tehran insists its activities have only civilian energy purposes and has refused to stop refining uranium, despite tightening sanctions.
"We (will) never stop enrichment activities in Iran," Soltanieh said, describing it as an inalienable right.
He declined to comment however on Western demands that Iran halt the higher-grade enrichment, to a fissile concentration of 20 percent, it began in 2010 and has since sharply expanded, shortening the time needed for any nuclear weapons breakout.
The U.N. Security Council has demanded in a series of resolutions since 2006 that Iran suspend all enrichment activity but Western diplomats have indicated the immediate priority is to get it to cease the more sensitive higher-grade work.
Many analysts say it will be possible to find a negotiated solution to the long-running row only if both sides compromise: Iran would be allowed to continue some lower-level enrichment if it accepts more intrusive U.N. inspections.
"There is a growing recognition that zero enrichment is not a feasible solution," said Mark Fitzpatrick, a director of the International Institute for Strategic Studies think-tank.
But the 27-nation European Union reiterated the aim to reach a diplomatic solution involving "the full implementation" of all relevant U.N. Security Council resolutions.
"Iran needs to engage in meaningful discussions on practical confidence-building steps in order to address the...concerns on its nuclear programme," said an EU statement delivered to a nuclear meeting in Vienna on Monday.
Editing by Mark Heinrich