The UN nuclear watchdog and Iran failed at talks on Friday to unblock a probe into suspected atom bomb research by the Islamic state, a setback dimming any chances for success in higher-level negotiations between Iran and major powers later this month.
The International Atomic Energy Agency, using unusually pointed language, said no progress had been made in the talks aimed at sealing a deal on resuming the IAEA's long-stalled investigation, and it described the outcome as "disappointing."
The setback came just a few weeks after UN nuclear chief Yukiya Amano said he had won assurances from senior Iranian officials in Tehran that an agreement would be struck soon.
Herman Nackaerts, the IAEA's global head of inspections, said after the eight-hour meeting at IAEA headquarters in Vienna that no date for further discussions on the matter had been set.
The IAEA had been pressing Tehran for an accord that would give its inspectors immediate access to the Parchin military complex, where it believes explosives tests relevant for the development of nuclear arms have taken place and suspects Iran may now be cleaning the site of any incriminating evidence.
The United States, European powers and Israel want to curb Iranian nuclear activities they fear are intended to produce nuclear bombs. The Islamic Republic says its nuclear program is meant purely to produce energy for civilian uses.
Six world powers were scrutinizing the IAEA-Iran meeting to judge whether the Iranians were ready to make concessions before a resumption of wider-ranging discussions with them in Moscow on June 18-19 on the decade-old nuclear dispute.
The lack of result may heighten Western suspicions that Iran is seeking to drag out the two sets of talks to buy time for its uranium enrichment program, without backing down in the face of international demands that it suspend its sensitive work.
"It should by now be clear to everyone that Iran is not negotiating in good faith," a senior Western diplomat said.
Nackaerts said the IAEA had come to the meeting with a desire to finalize the deal and had presented a revised draft that addressed earlier stated concerns by Iran.
"However, there has been no progress," he told reporters.
"And indeed Iran raised issues that we have already discussed and added new ones. This is disappointing. A date for a follow-on meeting has yet to be fixed."
Late last month, Amano returned from a rare, one-day visit to Tehran saying the two sides had decided to reach a deal and that he expected it to be signed soon.
Pierre Goldschmidt, a former chief UN nuclear inspector, said Iran probably did not want to make any concession to the IAEA just 10 days before the Moscow talks without getting something in exchange.
"It is indirectly a deliberate and unnecessary insult to Director-General Amano who recently went to Tehran in order to reach a deal," he said.
Mark Fitzpatrick, a former senior US State Department official and now a director at the International Institute for Strategic Studies think-tank in London, said:
"This situation is reminiscent of the Peanuts cartoon of Charlie Brown repeatedly believing Lucy this time will hold the football for him to kick, with her always snatching it away at the last minute, leaving him to fall flat."
Iran calls for more talks
Iran's IAEA ambassador, Ali Asghar Soltanieh, said after Friday's talks that work on a so-called "structured approach" document, setting the overall terms for the IAEA investigation, would continue and there would be more meetings.
"This is a very complicated issue," Soltanieh said. "We have decided to continue our work and we are going to decide on the venue and date soon ... and we hope that we will be able to conclude this structured approach."
Asked about Parchin, Soltanieh said: "That is in fact one of the problems. The more you politicize an issue which was purely technical it creates an obstacle and damages the environment."
Both Iran - which insists it will work with the UN agency to prove allegations of a nuclear weapons agenda are "forged and fabricated" - and the IAEA said earlier that significant headway had been made on the procedural document.
But differences persisted over how the IAEA should conduct its inquiry. The United States said this week it doubted whether Iran would give the IAEA the kind of access to sites, documents and officials it needs to get to the bottom of its suspicions.
"Opening discussions with Iran is easy; closing a deal is incredibly difficult," said Karim Sadjadpour of the Carnegie Endowment think-tank. "The graveyard of international diplomacy is littered with failed Iran deals."
The talks pursued by world powers are aimed at defusing tension over Iran's nuclear works that has led to increasingly tough Western sanctions on Iran, including an EU oil embargo from July 1, and stoked fears of another Middle East war.
Full transparency and cooperation with the IAEA is one of the elements the world powers - the United States, Russia, France, Britain, China and Germany - are seeking from Iran.
But they also want Iran to stop its higher-grade uranium enrichment, which Tehran says it needs for a research reactor but which also takes it closer to potential bomb material.
For its part, Iran wants sanctions relief and international recognition of what it says is its right to refine uranium.
"The lack of progress at the talks today casts a shadow on the upcoming Moscow talks," said US proliferation expert David Albright. "Iran appears once again to be choosing stonewalling over transparency and confrontation over negotiations."
But Cliff Kupchan, a Middle East analyst at consultancy Eurasia Group, said he did not expect the lack of progress in Vienna to have major implications for the Moscow talks.
"The Iranians always bob and weave before meeting with the (six world powers), trying to get leverage," he said.