By Fredrik Dahl
VIENNA (Reuters) - Six world powers demanded on Thursday that Iran fulfill a pledge to let international inspectors visit a military installation where the U.N. nuclear watchdog says explosives research geared to developing atomic bombs may have taken place.
The joint call demonstrated unusual unity among the powers on Iran ahead of a planned revival of high-level talks as well as widening disquiet about the nature of Tehran's nuclear quest, with Israel threatening last-ditch military action.
Iranian Supreme Leader Ayatollah Ali Khamenei welcomed comments by U.S. President Obama about a diplomatic "window of opportunity" offered by renewed talks, but said Washington's simultaneous moves to "bring the Iranian people to their knees" with harsh sanctions were driven by delusion.
Heaping pressure on Iran to come clean on its nuclear activity, the United States, Russia, China, Britain, France and Germany used a U.N. nuclear watchdog governors' meeting to urge Tehran to grant prompt access to its Parchin military facility.
They voiced concerned that no deal was reached between Iran and International Atomic Energy Agency inspectors at talks in January and February, "including on the access to relevant sites in Iran, requested by the agency ... In that context we urge Iran to fulfill its undertaking to grant access to Parchin."
Iran has said inspectors can go to Parchin, but only after a broader deal is reached on how to address all outstanding issues between Tehran and the U.N. agency -- an approach Western diplomats dismissed as a procedural stalling tactic.
GETTING RID OF EVIDENCE?
Western diplomats said this week they suspect Iran might be delaying a U.N. inspectors' trip to Parchin while it clears away evidence of explosives tests relevant to designing atomic bombs.
The six powers made no such accusation in their statement at a closed-door board session of the 35-nation International Atomic Energy Agency governing board.
But their language regarding Parchin and other aspects of Iran's shadowy nuclear program sent a message to Tehran of a cohesive stance within the group on how to diplomatically tackle the long-running stand-off, which has stirred fears of war that could inflame the Middle East and send oil prices skyrocketing.
The six powers voiced "regret" about Iran's escalating campaign to enrich uranium, which can yield material for electricity or nuclear bombs and is now focused in a mountain bunker chosen as protection from air strikes.
Iran, now facing sanctions targeting its oil exports for defying international demands to curb its nuclear activities, denies suspicions of a camouflaged bid to develop atom bombs, insisting it wants nuclear power for electricity generation.
But Israel, feeling in mortal danger from Iran's nuclear advances, openly doubts sanctions and diplomacy will rein in its arch-enemy's nuclear activity and is speaking more stridently of resorting to pre-emptive bombings of Iranian nuclear sites.
Dampening the saber-rattling, the European Union's foreign policy chief said on Tuesday the six powers had accepted Iran's offer to revive talks after a standstill of a year.
"We call on Iran to enter, without preconditions, into a sustained process of serious dialogue which will produce concrete results," the six powers said in their IAEA statement, read out by China's envoy to the U.N. watchdog.
The Islamic Republic's chief nuclear negotiator Saeed Jalili last month promised to float "new initiatives" at the talks, whose venue and date are not yet decided.
But Iran's ambassador to France, Ali Ahani, said on Thursday its "inalienable" right to enrich uranium would not be on the table [ID:nL5E8E897Z] - a stance redolent of past talks doomed by the two sides' inability to agree even on an agenda.
Iran has long declared its nuclear work non-negotiable and rejected, on sovereignty grounds, closer international inspections and oversight as guarantees that its enrichment activity remains peaceful, as called for by Western powers.
Ahani said all parties must be realistic in their approach to negotiations and the powers should not be worried by Iran's nuclear activities. "We have to try through dialogue to resolve them (issues) and reach a compromise and in my opinion it's better not to prejudge these negotiations in advance."
KHAMENEI PRAISES, RAPS OBAMA
Obama on Monday warned against "bluster" and "loose talk of war" over Iran, which he felt had driven up oil prices, and said he was convinced "that an opportunity remains for diplomacy - backed by pressure - to succeed".
Khamenei hailed Obama's remarks. "We heard two days ago that the U.S. president said that (they) are not thinking about war with Iran. These words are good words and an exit from delusion," Khamenei was quoted by IRNA as saying.
But Khamenei's praise for a U.S. leader, rare for Iran's paramount political figure, was tempered by criticism over what he called an Obama remark about "bringing "the Iranian people to their knees through sanctions".
"This part of his comments shows that the illusion continues," the paramount clerical leader said.
The United States has succeeded in severely limiting Iran's access to global financial services and in extending its own ban on Iranian oil to the European Union and beyond.
But Khamenei has said that no obstacle can impede Iran's nuclear drive, which he called a "pillar of national dignity".
Running out of patience with diplomacy, Israel has asked the United States for advanced "bunker-buster" bombs and refueling planes that could improve its ability to attack Iran's subterranean nuclear sites, an Israeli official said.
"Such a request was made" around the time of Israeli Prime Minister Benjamin Netanyahu's visit to Washington this week, the official said.
Israel is widely assumed to have the Middle East's only nuclear arsenal but its conventional firepower may not be enough to deliver lasting damage to Iran's distant, widely dispersed and well-fortified facilities, many experts say.
Reflecting its concern that Islamist militants could attack Israel in retaliation for an attack on Iran by tunneling in from neighboring Lebanon or Palestinian territories, Israel is training its troops to hunt below ground with robot probes and sniffer dogs.
An IAEA report last year revealed a trove of intelligence pointing to research activities in Iran of use in developing the means and technologies needed to assemble nuclear weapons, should it decide to do so.
One salient finding was information that Iran had built a large containment chamber at Parchin in which to conduct high-explosives tests that the IAEA said are "strong indicators of possible weapon development".
Iran, one of the world's largest oil producers, has dismissed intelligence reports suggesting it has a nuclear weapons agenda as forged and baseless.
IAEA chief Yukiya Amano this week said there were indications of unspecified "activities" at Parchin and that this made the agency want to visit the site sooner rather than later.
Suspicions about activities at the Parchin complex date back to at least 2004, when a prominent nuclear expert said satellite images showed it might be a site for nuclear weapons research.
U.N. inspectors did in fact visit Parchin in 2005. But they did not see the place where the IAEA now believes the explosives chamber was built.
(Additional reporting by John Irish in Paris, Marcus George in Dubai, Mayaan Lubell in Jerusalem; Writing by Mark Heinrich; Editing by Peter Millership)