The meeting was scheduled to start at 12:30 Tehran time, 10 am local time on Tuesday, however, it was postponed.
The ministerial meeting will focus on completion of text of comprehensive nuclear agreement and its appendixes.
Iranian Foreign Minister Mohammad Javad Zarif held a short meeting with US Secretary of State John Kerry a few hours ago.
On Monday, foreign ministers of Iran and 5 permanent members of UN Security Council plus Germany held two rounds of meetings, with participation of their deputies, to remove disagreements.
Sources close to Iran's nuclear negotiating team say talks are underway in Vienna very seriously, but the two sides are hopeful about removing the brackets.
Your Comment