Iranian media said the talks, which collapsed more than a year ago, would be held in Istanbul on Friday.
A return to the table, after more than a year of tightening sanctions over what the West believes is a program to develop nuclear weapons, had been in doubt after Iran and the P5+1 countries - the United States, Britain, France, Russia, China and Germany - released conflicting statements about the venue.
Tehran had earlier voiced concerns about holding them in Turkey, whose opposition to Iranian ally President Bashar Assad in Syria has angered the Islamic Republic.
“After weeks of debates, Iran and the six world powers agreed to attend a first meeting in Istanbul,” the semi-official Fars news agency reported, citing unnamed sources. State-run English language Press TV carried the same report.
The Fars news agency also said the sides had agreed to a second round of talks in Baghdad if there was progress in Turkey. There was no immediate comment on the venue from the world powers.
Turkey’s NTV news quoted Turkish prime minister Tayyip Erdogan as saying: “It wouldn’t be appropriate to make a statement on an issue that hasn’t been confirmed. As soon it’s confirmed, we will immediately share this with you.”
Getting Iran to suspend high-level uranium enrichment and close a nuclear facility built deep under a mountain near the holy city of Qom are “near-term priorities” for the United States and its allies, a senior US official said on Sunday.
The New York Times said the United States and other Western nations planned to demand Iran immediately close and ultimately dismantle the Fordow facility and also would call for a halt in the production of 20-percent enriched uranium.
The US official told Reuters “20 percent and closing Fordow are near-term priorities” for the Obama administration and its international partners in dealing with Iran.
Iran says its nuclear program is for power generation and producing isotopes for medical purposes, but the UN Security Council has demanded a full suspension of enrichment, both to the 20 percent and the 3.5 percent level.
Iran has enough 3.5 and 20 percent-enriched uranium for around four bombs if refined further to about 90-percent purity, Western experts say.
Earlier on Sunday, Israel, which has also demanded an end to all enrichment and has threatened attacks on its arch-foe’s nuclear facilities if diplomacy fails, signalled it would accept, as a first priority, the Western powers focusing on stopping 20-percent enrichment.
“We told our American friends, as well as the Europeans, that we would have expected the threshold for successful negotiations to be clear, namely that the P5+1 will demand clearly that - no more enrichment to 20 percent,” Israeli Defense Minister Ehud Barak said in an interview with CNN’s Fareed Zakaria GPS to be aired on Sunday.
Iran’s stocks of 20 percent-pure uranium should be removed “to a neighboring, trusted country,” Barak said, according to an advance transcript of the interview.
While Iran says it has a sovereign right to peaceful nuclear technology, it has at times appeared more flexible regarding 20 percent enrichment, which it began in early 2010, and some experts say that initially getting Iran to stop this higher-grade work could open a way to ease the deadlock.
It is not clear what Iran would expect in return, but an easing of some of the sanctions, which include an oil embargo by the European Union, might be among them.
Asked about Barak’s comments to CNN, another Israeli official confirmed that Prime Minister Benjamin Netanyahu’s government was focusing lobbying efforts on Iran’s 20-percent pure uranium, but said the long-term goal remained the ending of all its enrichment work.
“The understanding that has emerged in our contacts with the powers is that there should be a staggered approach,” the official told Reuters on condition of anonymity.
There was scant encouragement from Iran to signal it was ready for concessions.
In an address on Iran’s annual day to celebrate its nuclear achievements, President Mahmoud Ahmadinejad warned Western powers that Iran would continue its pursue swift scientific progress.
“The nuclear industry is like a locomotive that can carry other industries along with it. It is like the space industry that has raised tens of sub-industries under it and it is clear that we must continue on this path,” the Iranian state news agency quoted him as saying.
“You are blind if you think you can block scientific growth in Iran by martyring Iranian scientists,” he added referring to the killing of four Iranian scientists since 2010. “Don’t think you can stop this roaring river, and know that if you assassinate one scientist, hundreds and thousands will take his place.
The head of its parliamentary committee for national security and foreign policy, Alaeddin Boroujerdi, said late on Saturday that despite the climate of threats and sanctions, Iran was proficient in all stages of enrichment from mining raw uranium in Iranian mines, producing yellow cake (concentrated uranium powder), to building centrifuges and injecting uranium gas into them.
In February Iran announced it had loaded domestically made fuel rods into the Tehran Research Reactor, which produces radio isotopes for medical use and agriculture.
International sanctions are aimed at depriving the regime of funds and technology to further the nuclear program and are squeezing its vital oil exports and government finances.
