Vienna - Six world powers and Iran made a "good start" during talks in Vienna towards reaching a final settlement on Tehran's contested nuclear programme, the European Union's foreign policy chief Catherine Ashton on Thursday.
Speaking to reporters after three days of negotiations, Ashton said the two sides had identified the ingredients of an accord that could put an end to years of hostility between the West and the oil producing nation.
But she cautioned that future negotiations, which western governments want to wrap up by late July, would not be easy.
"We have had three very productive days during which we have identified all of the issues we need to address in reaching a comprehensive and final agreement," she told reporters.
"There is a lot to do. It won't be easy but we have made a good start."
Senior diplomats from the six powers - the United States, Russia, China, France, Britain and Germany - as well as Iran's Foreign Minister Mohammad Javad Zarif and Ashton agreed to meet again on 17 March, also in the Austrian capital.
‘Constructive and useful’
Although modest in scope, the agreement on an agenda for talks indicates an early step forward in the elusive search for a settlement in the nuclear dispute, which carries the risk of enveloping the Middle East in a new war.
The sides remain far apart on how to resolve the dispute and both Iran and the United States, a key player in the talks, have publicly stated it may not be possible to reach a final agreement.
A senior US State Department official said of Wednesday's second day of talks: "Today's discussions, which covered both process and substance, were constructive and useful".
The six powers want a long-term deal on the permissible scope of Iran's nuclear work to lay to rest concerns that they could be put to developing atomic bombs. Tehran's priority is a complete removal of damaging economic sanctions against it.
The powers have yet to spell out their precise demands of Iran.
But Western officials have signalled they want Tehran to cap enrichment of uranium at a low fissile concentration, limit research and development of new nuclear equipment, decommission a substantial portion of its centrifuges used to refine uranium, and allow more intrusive UN nuclear inspections.
Such steps, they believe, would help extend the time Iran would need to make enough fissile material for a bomb and make such a move easier to detect before it became a fait accompli. Tehran says its programme is peaceful and has no military aims.
Wide differences over expectations remain, however. Iran's Deputy Foreign Minister Abbas Araqchi was cited by Press TV on Tuesday as saying Iran would not agree to dismantle its nuclear installations.