VIENNA (Reuters) - U.N. nuclear experts' talks in Iran appear to have made little concrete progress, diplomats said on Thursday, setting the stage for a crucial second round this month over Western fears Tehran may aim to build atomic weapons.
Three days of discussions in Tehran which ended on Tuesday were a rare direct dialogue in the long-running international dispute, which has deepened as the West pursues a punitive embargo on Iranian oil and Tehran threatens retaliation. There are fears the confrontation could lead to a military conflict.
Senior officials from the International Atomic Energy Agency plan to return to Tehran for more discussions on February 21 and 22 after holding what both sides publicly described as good talks.
Herman Nackaerts, IAEA deputy director-general, told reporters on his return from Tehran on Wednesday that more work remained to be done. Asked if he was satisfied with the talks, Nackaerts said: "Yeah, we had a good trip."
Now diplomats are trying to glean whether Nackaerts was simply being polite, or really meant the visit was fruitful.
"It does seem to us that there has just been no indication of any substantive progress during this meeting, that Iran was very focused on process and modalities and not engaging the IAEA on answering the questions or providing the information and access that they have been asking for," one envoy said.
Another diplomat described the latest talks as "long, intensive discussions about procedures, issues, but no discussion on concrete issues."
But he acknowledged there had been "some headway" to start substantive talks that now had to be fleshed out.
"To summarize it: talks about procedures and how to proceed and then probably next time they have to fix the issue of access," he said.
One Western diplomat said he understood the IAEA team had sought - but not been granted - access to the Parchin military site mentioned in a report the agency drew up in November spelling out why it was concerned about Iran's ambitions.
But he and other analysts pointed out the scheduling of a return trip to Tehran at least held out some hope of progress.
"Failure was really an option," he said of the prospects before Nackaerts and his colleagues flew to Tehran. But he added: "They did not fail."
The secretive, Vienna-based IAEA would not comment officially on the visit beyond a formal statement issued on Wednesday in which Director General Yukiya Amano said: "The Agency is committed to intensifying dialogue. It remains essential to make progress on substantive issues."
Tehran says its uranium enrichment program is solely for peaceful electricity generation and has dismissed as baseless allegations that it is seeking to develop nuclear weapons.
The standoff has spawned three years of deadlock in efforts to resolve the questions about Tehran's nuclear work.
The IAEA has said it explained to Iran its "concerns and identified its priorities, which focus on the clarification of possible military dimensions" to Iran's nuclear program.
"The IAEA also discussed with Iran the topics and initial steps to be taken, as well as associated modalities," it said.
In Tehran, Iranian Foreign Minister Ali Akbar Salehi said on Wednesday more talks would be needed.
"We had very good meetings and we planned to continue these negotiations. The team had some questions about the claimed studies. One step has been taken forward," he told the semi- official Fars news agency.
By "studies," Salehi was alluding to intelligence reports indicating that Iran has covertly researched ways to design a nuclear weapon. Salehi added: "We were ready to show them our nuclear facilities, but they didn't ask for it."
Lower-level IAEA inspectors based in Iran have regular, if limited, access to Iran's declared nuclear installations.
Western diplomats have often accused Iran of using offers of dialogue as a stalling tactic while it presses ahead with stockpiling enriched uranium, the key energy source in nuclear power plants or bombs, depending on the level of refinement.
Israel's military intelligence chief said on Thursday that Iran had stockpiled sufficient enriched uranium that, if processed much further, could provide material for four nuclear weapons.
Friction between Iran and the West worsened this year after the United States and the European Union imposed sanctions targeting Tehran's oil sector over its continued defiance of U.N. resolutions demanding it suspend enrichment, grant unfettered access to the IAEA and engage in negotiations.
Iran has been open to resuming talks with six world powers frozen for over a year but only to discuss broader international issues, not its nuclear program.
The new Western measures take direct aim at the ability of OPEC's second-biggest oil exporter to sell its crude. Iran has threatened to cut off oil exports to EU countries before July 1, when the sanctions would take full effect.
The reluctance of major powers China and Russia to support more sanctions, and the willingness of Asian nations to go on buying Iranian oil, has frustrated Western governments.
Visiting Beijing on Thursday, German Chancellor Angela Merkel urged China to use its influence with Iran to persuade it to comply with Western demands on its nuclear program.
(Editing by Alastair Macdonald)