Spokesman of EU foreign policy chief Catherine Ashton said on Tuesday they were taking place in a "positive atmosphere".

Michael Mann added that Iran presented a new plan on how to resolve the stand-off.

"I hope it is really time now for tangible results," Mann said, pointing to a string of previous fruitless talks.

The spokesman did not share the details of Iran's power point presentation but says experts accompanying Ashton and envoys of five UN veto powers and Germany would analyze it quickly.

The talks were the first since President Hassan Rouhani took office in August.

He has vowed to solve the 10-year nuclear standoff quickly, in order to get crippling international sanctions lifted.

Iranian Foreign Minister Javad Zarif met the EU foreign policy chief, who led a delegation of diplomats from the five permanent UN Security Council member countries and Germany.

Ashton said she expected Iran to present new ideas in response to an offer made by the international group in April. The plan foresees the easing of some sanctions, in return for curbs on Iran's uranium enrichment production and increased transparency on its programs.

Britain, China, France, Russia, the US and Germany - a group known as the P5+1 - are concerned that Iran could use its enriched uranium
for nuclear weapons, while Tehran's leaders insist they need the material only to fuel reactors for civilian use.

NTJ/BA