|Iranian officials have warned that the talks will fail if 'pressure' is used to stop the nuclear programme [Reuters]
Proposed talks on Iran's nuclear programme must be without "pre-conditions" and produce "concrete results", world powers have said.
"We call on Iran to enter, without pre-conditions, into a sustained process of serious dialogue, which will produce concrete results," a statement issued on Thursday said.
The statement, issued on behalf of the United States, China, Russia, France, Britain and Germany, known as the P5+1, added that the countries' readiness to negotiate was "on the understanding that these talks will address the international community's long-standing concerns and that there will be serious discussions on concrete confidence building measures".
The statement was read out by China's envoy to the United Nations atomic watchdog, the International Atomic Energy Agency, at a closed-door regular board meeting at its Vienna headquarters in Austria.
On Tuesday, Catherine Ashton, the European Union foreign policy chief, said on behalf of the six powers that they were ready to hold talks with Iran. The details of where and when the negotiations would be held have not yet been decided.
The last round, which took place in Istanbul, Turkey, in January 2011, broke down, according to Western diplomats, over Tehran's demand to discuss "preconditions" before dealing with specifics in the nuclear dispute.
Ashton said in a letter to Saeed Jalili, the chief Iranian nuclear negotiator, that the powers did not want to "repeat the experience of Istanbul" and that the dialogue "will have to focus" on the "key issue" of Iran's nuclear programme.
Ali Larijani, Iran's parliamentary speaker, warned that the talks would fail if they were used to "pressure" Tehran.
The White House said on Wednesday that in the talks Washington "will demand that Iran live up to its international obligations - that it provide verifiable assurances it is not pursuing a nuclear weapon."
Ali Asghar Soltanieh, Iran's envoy to the IAEA, refused comment on what concessions Iran may make in order to facilitate the planned talks.
Tehran's willingness to discuss with the IAEA allegations of a nuclear weapons programme "by itself is confidence building," he told reporters.
"We will never suspend our nuclear activities, and we will continue [with them], under the supervision of course of the IAEA," he said.
The possible resumption comes despite an apparent deadlock between the IAEA and Iran after two fruitless visits to Tehran led by chief inspector Herman Nackaerts in January and February this year.
The visits saw Iran again reject a major IAEA report in November that alleged that suspicious nuclear activities were ongoing at several sites. Iran also denied access to the Parchin military site where the IAEA alleges that explosives testing for warhead research had taken place.
Thursday's P5+1 statement urged Iran to "fulfil its undertaking to grant access to Parchin".
Yukiya Amano, the IAEA's chief, on Monday appeared to allege that Iran was removing evidence at the base, saying "activities" spotted by satellite "makes us believe that going there sooner is better than later."
Iran says that the IAEA already cleared the Parchin site in 2005, and that it was under no obligation to allow access to what it terms a non-nuclear site.
Nackaerts said that since 2005 "we have acquired new information - from satellite imagery - from which we have been able to identify the precise location where we believe an explosive chamber is situated".
Iran is highly sensitive about allowing access to military sites following a large explosion at the Bid Ganeh base in November and multiple assassinations of nuclear scientists it has blamed on Israel and the United States.
Soltanieh said allegations of "sanitisation" of the site were "a childish [and] ridiculous story made out of nothing", describing Parchin as "one minor issue" in its negotiations with the IAEA, which he said were ongoing.
"Unfortunately, Western countries are not telling the truth ... The truth is that Iran is not pursuing nuclear weapons," with sanctions having "no effect whatsoever" on Iran's nuclear activities, including enrichment, he said.