Vienna, Feb 20 (IANS): The talks on Iran's nuclear programme concluded Thursday after Iran and the six world powers agreed on an action plan and framework of comprehensive negotiation for the final step.

After two days of intensive talks, Iranian Deputy Foreign Minister Abbas Araqchi said the two sides reached an agreement during negotiations that were held in a positive atmosphere, but he could not be optimistic yet about progress in future talks, reported IRNA news agency.

About the time and venue of the next round of talks between Iran and P5 1 -- China, Britain, France, Russia, and the US plus Germany -- Araqchi, who is also a member of Iran's nuclear negotiating team, said the next round will be held in March in Vienna.

Araqchi said Iranian Foreign Minister Mohammad Javad Zarif and European Union foreign policy chief Catherine Ashton would declare results of the talks in a joint press conference later Thursday.

The Iranian nuclear talks are based on the interim deal agreed in Geneva in November last year, in which Iran suspended most of the sensitive facets of its nuclear activities in exchange for partial relief in sanctions slapped on it.

The parties involved are striving to clinch a comprehensive deal over the decade-long nuclear standoff.