Iran to hold key nuclear talks at UN
Iran's foreign minister will meet six major world powers at the UN this week to discuss Tehran's nuclear programme, US and EU officials say.
The talks with Iranian FM Mohammed Javad Zarif will include US Secretary of State John Kerry - the highest level US-Iran meeting for more than 30 years.
Talks will take place on the sidelines of the UN General Assembly in New York.
Iran's new President Hassan Rouhani has said he is ready to restart stalled nuclear talks without preconditions.
In a separate development, Tehran said it had pardoned 80 prisoners.
Among them are a number of those who were arrested over protests following the disputed presidential election in 2009.
The move comes a few days after a pardon was issued to 11 inmates.
EU foreign policy chief Catherine Ashton said Mr Zarif, who is also Iran's chief nuclear negotiator, would this week meet foreign ministers from the five permanent UN Security Council members - Britain, China, France, Russia and the US - and also Germany (the P5+1 group).
"We had a good and constructive discussion," Baroness Ashton said after her talks with Mr Zarif at the UN on Monday.
She said she had been struck by the "energy and determination" that she had seen from the Iranians ahead of this week's UN General Assembly.
And the EU official added that her team would hold talks with Mr Zarif again in October in Geneva to assess the progress.
A US State Department official quoted by AFP news agency cautioned that "no-one should have the expectation that we're going to resolve this decades-long issue during the P5+1 meeting later this week".
The official said the "ball was firmly in Iran's court".
The meetings at the sidelines of the UN General Assembly are part of a charm offensive by Mr Rouhani, the BBC's Bridget Kendall in New York reports.
In 2007, then-Secretary of State Condoleezza Rice was supposed to be seated next to then-Foreign Minister Manouchehr Mottaki at a summit dinner in Egypt, but Mr Mottaki stayed away from the dinner.
Last week, Mr Rouhani said that his country would never build nuclear weapons.
In an interview with the US broadcaster NBC, the president stressed that he had full authority to negotiate with the West over Tehran's uranium enrichment programme.
And he described a recent letter sent to him by US President Barack Obama as "positive and constructive".
A White House spokesman said Mr Obama's letter "indicated that the US is ready to resolve the nuclear issue in a way that allows Iran to demonstrate that its nuclear programme is for exclusively peaceful purposes".
"The letter also conveyed the need to act with a sense of urgency to address this issue because, as we have long said, the window of opportunity for resolving this diplomatically is open, but it will not remain open indefinitely," the spokesman added.
The latest moves come amid suggestions that Mr Obama and Mr Rouhani may meet on the sidelines of the General Assembly and shake hands.
In his election campaign earlier this year, Mr Rouhani pledged a more moderate and open approach in international affairs.
Iran is under UN and Western sanctions over its controversial nuclear programme.
Tehran says it is enriching uranium for peaceful purposes but the US and its allies suspect Iran's leaders of trying to build a nuclear weapon.