High-ranking officials from Iran and the Group 5+1 (the US, Russia, China, Britain and France plus Germany) started the third round of their talks in Vienna on Tuesday morning to work out a permanent and comprehensive agreement over Tehran's nuclear program. The talks were inaugurated at the UN headquarters in the Austrian capital city of Vienna headed by Iranian Foreign Minister Mohammad Javad Zarif and EU Foreign Policy Chief Catherine Ashton. The negotiations presided by Zarif and Ashton's deputies Seyed Abbas Araqchi and Helga Schmidt, respectively, will continue until Thursday. Nuclear experts from Iran and the Sextet of the world powers had three days of talks in Vienna from Thursday to Saturday afternoon. Speaking after the last session of talks, the Iranian Foreign Ministry's Director-General for Political and Legal Affairs, Hamid Baeidinejad who led the Iranian delegation, described the negotiations with the expert teams of the six world powers as "useful". The talks between Tehran and the six world powers are part of efforts to seal a final deal on Iran’s nuclear energy program. Iran and the Group 5+1 representatives had several sessions of talks in Vienna on March 18-19. On November 24, Iran and the Group 5+1 (the five permanent United Nations Security Council members plus Germany) sealed a six-month Joint Plan of Action to lay the groundwork for the full resolution of the West’s decade-old dispute with Iran over the latter's nuclear energy program. In exchange for Tehran’s confidence-building bid to limit certain aspects of its nuclear activities, the Sextet of the world powers agreed to lift some of the existing sanctions against Tehran and impose no nuclear-related sanctions on Iran during the six-month period.