EU foreign affairs representative Catherine Ashton has held talks with Iran's chief nuclear negotiator, Saeed Jalili, in a bid to end the stand-off over the Iranian nuclear programme.
The EU said the meeting in Istanbul, which ended early on Wednesday, was "useful and constructive".
Mr Jalili said they assessed "common points" reached by technical teams.
Talks in June between Iran and the P5+1 - the US, UK, France, China, Russia and Germany - ended without a breakthrough.
US Secretary of State Hillary Clinton said afterwards that the proposals they had seen from Iran had been "non-starters".
State department spokeswoman Victoria Nuland said the purpose of Tuesday's meeting was to gauge whether the Iranians were "prepared to bring anything new".
'Rights and concessions'
The talks between Baroness Ashton and Mr Jalili, the secretary of Iran's Supreme National Security Council, were not considered formal negotiations.
Afterwards, an EU spokesman said in a brief statement that it had been "a useful and constructive meeting and an important opportunity to stress once again to Iran the urgent need to make progress".
Baroness Ashton would brief representatives of the P5+1 next week on the sidelines of the UN General Assembly in New York, it added.
Mr Jalili said he and the EU's foreign policy chief had assessed some proposals agreed at a lower-level technical meeting in July.
"We discussed common points found by the experts and technical teams... so that they may be brought closer together and that a framework for future talks can be drawn," he added. "We hope [our] talks can help bring the common points closer together."
"We are awaiting the result of the six powers' assessment."
On Monday, the head of the Atomic Energy Organisation of Iran said the UN's International Atomic Energy Agency might have been infiltrated by "terrorists and saboteurs" who "might be making decisions covertly".
Fereydun Abbasi-Davani cited an incident on 17 August, when power lines from the city of Qom to the underground uranium enrichment facility at Fordo were cut, shortly before an unscheduled visit by IAEA inspectors.
His comments came days after the IAEA's governing body expressed "serious concern" that Iran had continued to defy UN Security Council resolutions demanding it suspend uranium enrichment and had failed to resolve questions about possible nuclear weapons development.
On Sunday, Israeli Prime Minister Benjamin Netanyahu warned that Iran was only six or seven months from having "90%" of what it needed to make a nuclear bomb, and urged the US to draw a "red line" which if crossed would lead to military intervention.
Iran has insisted that its nuclear programme is solely for peaceful purposes, and warned that it will retaliate if it comes under attack.