EU foreign policy chief Catherine Ashton, who heads global nuclear talks with Iran, Tuesday said it was urgent to return to negotiations as "the window of opportunity is closing."
Ashton, who represents six world powers seeking to convince Iran to freeze its disputed nuclear programme, insisted in a hearing with the EU parliament's foreign affairs committee that she would look for a solution when talks with Tehran finally resume.
"I am looking for a solution. I don't believe it will be done in one discussion. I do believe it can be done," she added.
On behalf of Britain, China, France, Germany, Russia and the United States, Ashton has offered to resume stalled talks with Iran but a time and venue still need to be agreed.
Western powers suspect Iran is seeking to build a nuclear bomb, a charge denied by Tehran, which says its atomic programme is for peaceful purposes.
After several failed rounds, the last in Istanbul just over a year ago, the powers agreed to resume the talks after receiving a written commitment by Iran to address the nuclear issue at the negotiations.
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In Istanbul, Iran refused to address questions on its nuclear programme, demanding what diplomatic sources dubbed "pre-conditions", such as the lifting of sanctions.
But in a February 14 letter to Ashton, Iran's chief nuclear negotiator Saeed Jalili said Tehran was ready to resume the deadlocked talks as long as its right to peaceful atomic energy was respected.
"We're ready to sit down with them" on the basis of Jalili's letter, Ashton said.
"But you will also appreciate that we are talking with a purpose and it will be very, very important that it becomes clear quickly that there is a real purpose to these talks," she said.
"That for me is going to be the basis upon which we will start; with respect to Iran, but with a clarity that we want to see progress within a good reasonable time."
Jalili's letter, a long-belated response to one from Ashton in October, came as world powers moved to adopt unprecedented economic sanctions against Tehran, including an EU oil ban due to come into force on July 1.
Sanctions were ramped up in the last months after the UN's International Atomic Energy Agency said in a report it had evidence the Islamic republic appeared to be conducting research on atomic warheads.
"It's very, very important that we have sanctions that are designed to persuade Iran to come to the table," Ashton said, but added: "The purpose is not to hurt the population of Iran."