The US had said that it doubted whether Iran would give the IAEA the kind of access it needs.
Iran, UN can't agree on suspected nuke site
Iran and the United Nations' nuclear watchdog failed to reach a deal last night in talks that aimed to permit an investigation into "possible military dimensions" to Tehran's atomic programme.
"There has been no progress," the International Atomic Energy Agency's (IAEA) chief inspector Herman Nackaerts told journalists after a day of talks with Iran's envoy to the IAEA, adding that the result was "disappointing".
A breakthrough in Vienna would have given encouragement to the US, Britain, Russia, China, France and Germany - the P5+1 - preparing for wider, critical negotiations with Iran on its nuclear activities later this month in Moscow.
The US had said this week that it doubted whether Iran would give the IAEA the kind of access it needs.
The mistrust was mutual.
Fulfilling the "demands" of the IAEA's chief, Yukiya Amano, "will take 200 years", wrote Hossein Shariatmadari, the editor of Tehran's hardline Kayhan newspaper and an aide to Iran's supreme leader, Ayatollah Ali Khamenei.
The IAEA was seeking immediate access to the Parchin military complex near Tehran where it suspects Iran may have tested explosives that could be used in nuclear weapons triggers.
Iran, which insists its nuclear programme is solely peaceful, has rejected the allegations about Parchin as "childish" and "ridiculous", saying they were based on "fabricated documents" provided by hostile spy agencies. Iran has barred access to Parchin for four years, arguing it is a conventional military site, not a nuclear one, and therefore none of the IAEA's business.
Ali Asghar Soltanieh, Iran's envoy to the IAEA, this week accused the UN body of acting like a western-manipulated spy service.
The UN's nuclear watchdog was also hoping to gain access to Iranian scientists and sensitive documents. The IAEA has long sought explanations for intelligence information, described as "credible" in a report by the agency last November, pointing to research on the design and testing of nuclear warheads until 2003 and possibly beyond.
The IAEA's dealings with Iran are separate from Tehran's negotiations with the P5+1 but the two tracks are related.
Tehran came under rare public pressure yesterday from China, a major importer of Iranian oil that opposes further sanctions, to show "flexibility and pragmatism" in talks with the six world powers.
The remarks by the Chinese leader, Hu Jintao, came in a meeting in Beijing with Mahmoud Ahmadinejad, Iran's president.
He has been shut out of the nuclear talks by Ayatollah Khamenei. But Mr Ahmadinejad stirred the pot on Thursday by declaring that "if Iran wants to build an atom bomb, it doesn't fear anyone and will publicly announce it and no one will be able to prevent it".
At the same time, he insisted Iran has no intention of building nuclear weapons.
A deal with the IAEA in itself would not have been enough to allay international concerns. The West's immediate aim is to get Iran to relinquish its enrichment of uranium to 20 per cent, which is a short technological step from producing bomb-grade material. Iran says it is only purifying to this level for the purposes of medical research but the issue will be the focus of the Moscow talks.
At talks in Baghdad last month, the P5+1 offered Iran modest inducements to surrender its 20 per cent enrichment, rejecting Tehran's calls for early and significant sanctions relief in return for any such concession. The EU, which recently accounted for 18 per cent of Iran's oil shipments, plans to begin a boycott on July 1.
One former Iranian nuclear negotiator, Hossein Mousavian, scoffed that the West had offered Iran peanuts in exchange for diamonds.
Iran has hinted it could compromise on its higher-enriched uranium if the price is right, but vows it will never relinquish purification to 3.5 per cent, the level required to fuel electricity-generating nuclear reactors.
Both sides have strong incentives to keep the negotiations going. Iran needs sanctions relief while Barack Obama, the US president, fears that a failure of the talks could bring an Israeli attack on Iran that would drive up oil prices, jeopardising his re-election bid.
with additional reporting by Agence France-Presse