The UN atomic watchdog and Iran have hailed "productive" talks, in the latest possible sign of Tehran's willingness to ease international concerns about its nuclear work.
Iran's envoy to the International Atomic Energy Agency said he presented new proposals - aimed at clearing up allegations of past nuclear weapons research - that he hopes will "open a new chapter of cooperation".
The two sides will meet again in Tehran on November 11, a few days after parallel talks with the P5+1 group of six world powers - the five permanent members of the UN Security Council plus Germany - in Geneva on November 7-8.
The two-day meeting in Vienna was one of a series of gatherings this week meant to prepare the groundwork for that Geneva meeting.
"Iran presented a new proposal on practical measures as a constructive contribution to strengthen cooperation and dialogue with a view to future resolution of all outstanding issues," IAEA chief inspector Tero Varjoranta said.
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No details of the new proposal were given but Varjoranta called the talks "very productive".
The IAEA conducts regular inspections of Iran's nuclear activities but it also wants to probe evidence suggesting that Iranian scientists conducted experiments aimed at developing a nuclear arsenal.
Iran has consistently denied the allegations, saying the IAEA's claims are based on faulty foreign intelligence.
Ten meetings between Iran and the IAEA since a major report from the UN body in November 2011 have failed to make any progress, but Hassan Rouhani's election as Iranian president in August has precipitated a change in tone.
Rouhani has also created optimism for progress in Iran's parallel talks with world powers, which are focused more on Iran's current activities, most notably uranium enrichment.
Iran denies seeking or ever having sought to build the atomic bomb while steadily expanding its nuclear program over the years in defiance of multiple UN Security Council resolutions and sanctions.
