By Fredrik Dahl
VIENNA (Reuters) - The U.N. atomic watchdog and Iran appeared to make little real headway in talks last week and it is uncertain whether Tehran's more positive attitude will help yield a long-sought breakthrough, diplomats said on Wednesday.
Iran told the International Atomic Energy Agency in Friday's meeting it wanted to achieve substantive results within months in the talks on a stalled IAEA inquiry into suspected atomic bomb research by the Islamic state, one envoy said.
But he and others briefed on the closed-door discussions stressed that hopes had been raised before in Iran-IAEA meetings since early 2012, only to be dashed by what Western states saw as Iranian stonewalling. Iran denies any nuclear weapon aims.
The first talks between Iran and the IAEA since Hassan Rouhani took office as Iranian president were watched in the West for any sign of a shift by Tehran from the defiance of his hardline predecessor, Mahmoud Ahmadinejad.
The election in June of Rouhani, a relative moderate who has pledged to try to end the decade-old nuclear dispute with the West, has fuelled hopes of a peaceful resolution to a protracted row that could otherwise flare into a new Middle East war.
One Western diplomat said he had the impression that Iran and the IAEA were relatively "optimistic" after the meeting in Vienna, where the U.N. agency is based. Another envoy said the discussions had been focused and the atmosphere positive.
Both sides, including the new head of Iran's delegation, described their discussions as "constructive" and said the next meeting would be held on October 28 but gave no detail.
The IAEA talks are distinct from Iran's meetings with world powers, but both diplomatic tracks center on suspicions that Iran may be seeking the capability to assemble nuclear bombs behind the facade of a civilian atomic energy programme.
Iran says its nuclear programme is a peaceful bid to generate electricity, and not aimed at building weapons. But its refusal to curb sensitive nuclear work and lack of full openness with the IAEA has drawn increasingly harsh Western sanctions.
The Iran-IAEA meeting was a "good harbinger of better relations", said Mark Fitzpatrick of the International Institute for Strategic Studies, a London-based think tank.
"There is a new mood of optimism in Vienna that finally there is a way forward," Fitzpatrick said.
The IAEA wants access to sites and officials for its probe into what it calls the possible military dimensions to Iran's nuclear programme. Iran has dismissed allegations that it may have worked on designing a nuclear bomb as forged or baseless.
Eleven meetings since January last year have failed to end the deadlock over how the IAEA should conduct the investigation.
But Iran has pledged, since Rouhani took office in August, to increase its cooperation with the IAEA and it appointed a new envoy to the U.N. agency in August.
The next IAEA talks will take place about two weeks after Iran meets six world powers in Geneva in mid-October.
Western diplomats have long suspected that Iran might only agree to provide the IAEA with the access it wants as part of a broader settlement that wins it significant sanctions easing in return for scaling back its nuclear programme.
The six powers - the United States, France, Britain, Germany, China and Russia - "have to make sure that their desire to solve this crisis once and for all doesn't sacrifice" the IAEA's investigation, nuclear expert Mark Hibbs of the Carnegie Endowment think tank said.
"The IAEA can't simply ignore what Iran has done in the past because it is politically expedient," Hibbs said.
(editing by Elizabeth Piper)