The top negotiator with Iran over its disputed nuclear drive said Wednesday that she would consult with UN partners in New York after face-to-face talks overnight with Iran's Saeed Jalili.
European Union foreign affairs chief Catherine Ashton aims to meet with world powers in the coming days "in order to assess the situation and to discuss the way forward," her office said after the first direct talks since June on Tuesday night.
The foreign ministers of Britain, China, France, Russia, the United States and Germany are due in New York for the United Nations General Assembly going into a "ministerial week" due to begin formally on September 24.
Ashton plans to meet these key figures in the margins of the UN talks, in a bid to get stop-start international diplomacy over Tehran's contested atomic programme back moving.
No statements were made to the press at the beginning of Tuesday's meeting with Iran's top nuclear negotiator Jalili, which was held behind closed doors at the Iranian consulate in the Turkish city of Istanbul, starting at around 1930 GMT Tuesday.
Described simply as part of ongoing efforts "to seek a diplomatic solution," the talks followed negotiations in Moscow in June, a meeting of the respective heads' deputies in July and phone calls made over the summer, Ashton's statement said.
"While it was not a formal negotiating round it was a useful and constructive meeting and an important opportunity to stress once again to Iran the urgent need to make progress," said the declaration issued by EU High Representative Ashton's spokesman Michael Mann.
World powers have asked Iran to immediately stop enriching uranium because of fears Tehran might be developing nuclear weapons.
But Iran rejects the allegations, saying its nuclear programme is peaceful, designed for energy and development purposes only.
Jalili met earlier Tuesday with Turkey's Foreign Minister Ahmet Davutoglu to discuss the resumption of international talks over Tehran's atomic programme, a diplomatic source said.