EU foreign policy chief Catherine Ashton on Friday urged Iran to reply "in the next few days" to her proposal to resume long-stalled talks over its nuclear programme, her office said.

Ashton, who represents world powers in the nuclear dialogue with Iran, earlier this month offered to hold the talks in Vienna in mid-November.

"While Iran has indicated through the media that they welcome the offer... she is still awaiting a formal response," a spokesman for Ashton said.

"She is looking forward to Iran formally responding positively to her proposal in the next few days to make this happen," he added.

In a letter sent Friday to the Iranian authorities seen by AFP, Ashton's office reiterated the proposal to hold the meeting in or near Vienna from November 15 to 17.

"Given the proximity of the suggested dates and the diary constraints of the parties involved, I do hope for your early and positive response," it said.

A week ago Iran's Foreign Minister Manouchehr Mottaki dubbed Ashton's offer to resume talks "good news".

And the country's top nuclear negotiator Saeed Jalili said at the time on Tehran television that "Iran welcomes the return to negotiations".

Comenting for the first time on the proposed resumption of talks, President Mahmoud Ahmadinejad said negotiations were the only solution.

"We said from the start that the best way is to talk to Iran. You don't have any other option. All other ways are blocked," said Ahmadinejad.

Friday's letter from Ashton's office, addressed to Iran's EU ambassador, suggested starting the talks with a dinner on November 15 followed by two days of consultations.

"The main focus of the meeting would be on the question of the Iranian nuclear programme, not excluding any other items pertinent to the discussion," it said.

The nuclear negotiations aim to address international suspicion that Iran is seeking to develop atomic weapons under the guise of a civilian nuclear programme, a charge Tehran vehemently denies.

Dialogue between Iran and the group of 5+1 nations which Ashton represents -- Britain, China, France, Russia, the United States and Germany -- has been stalled since October 1, 2009, when the two groups met in Geneva.

Faced by deadlock, the United Nations Security Council on June 9 reinforced international economic sanctions, with the United States and EU taking separate measures -- all of which Tehran brushed off as having no impact.

Sanctions notably ban investments in oil, gas and petrochemicals while also targeting banks, insurance, financial transactions and shipping.

Tehran this week said it was ready to discuss the issue of exchanging atomic fuel in upcoming talks with world powers about its overall nuclear programme.

"We are ready to hold simultaneous talks with the 5+1 and the Vienna group about the fuel swap," ISNA quoted Iran's atomic chief Ali Akbar Salehi as saying.

Iran's separate negotiations with the Vienna group -- France, Russia, the United States and the UN atomic watchdog -- over the issue of procuring nuclear fuel for a Tehran-based research reactor have also been blocked since last October.