EU foreign affairs head Catherine Ashton will meet Iranian Foreign Minister Mohamad Javad Zarif on Wednesday in New York for further talks on Tehran's contested nuclear programme, her spokeswoman said.
There will be additional "negotiating sessions" ahead of formal discussions between Iran and the P5+1 powers -- the UN Security Council permanent members, Britain, China, France, Russia and the United States, plus Germany -- Ashton's spokeswoman said.
These P5+1 talks will take place on Friday on the sidelines of the UN General Assembly meetings in New York, the spokeswoman added.
Zarif and Ashton will hold a working lunch, his deputy Abbas Araqchi told Iranian state news agency IRNA on Tuesday.
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The United States and its allies suspect Iran wants to acquire nuclear weapons. Tehran insists its programme is purely peaceful and designed for civilian use only.
Late last year, the two sides agreed an outline deal which offered an easing of some sanctions against Iran in exchange for its agreement to curb some nuclear activities.
The accord went into effect in January but while they missed a July 20 deadline despite intense negotiations, all parties agreed to extend the agreement to November 24 in the hope of getting a final settlement.
The main sticking point remains Western concern over Iran's capacity to enrich uranium, a process that can make fuel for peaceful nuclear uses but also the core of an atomic bomb.
At the last talks in Vienna earlier this month, Iranian officials voiced some optimism about the talks but also warned of a "difficult road" ahead.