Deputy foreign ministers of Iran and Group 5+1 ended their 5-hour nuclear talks in Vienna on Thursday night, IRNA reported.
Abbas Araqchi and Majid Takht-e Ravanchi of Iran and EU deputy foreign policy chief Helga Schmid and US undersecretary of state Wendy Sherman took part in intensive negotiations in Vienna.
Iranian official accompanying the negotiators told IRNA that other deputy foreign ministers of Group 5+1 would join them in a matter of hours.
Deputy foreign ministers of Germany, Britain and France were on way to the venue and deputy foreign ministers of China and Russia had arrived in Vienna accordingly.
Iran and the G5+1 are in talks to hammer out a comprehensive accord to end more than a decade of impasse over Iranian nuclear program.
On April 2, the two sides reached a framework nuclear agreement in Lausanne, Switzerland, with both sides committed to push for a final deal until the end of June.