VIENNA - Iran nuclear talks will finish early on Thursday morning after Iran and the P5+1 - China, Britain, France, Russia, the United States plus Germany - have agreed on an agenda and a framework.

Iranian Deputy Foreign Minister Abbas Araqchi told the official IRNA news agency that the involved parties of Iran nuclear talks have agreed on an agenda and a framework and the next round of talks will be in the second half of March in Vienna.

An American diplomat told Xinhua that the discussion on Wednesday evening, which covered both process and substance, were constructive and useful, adding that a plenary meeting with the involved parties starts at 9 am on Thursday morning.

EU foreign policy chief Catherine Ashton's spokesman also confirmed that Ashton would leave for Brussels to attend an extraordinary meeting of EU Foreign Ministers on Ukraine scheduled for Thursday.

The Iranian nuclear talks are based on the interim deal agreed in Geneva in November 2013, in which Iran suspended the most sensitive parts of its nuclear activities in exchange for partial relief of the sanctions slapped on it.

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