Iranian chief negotiator for nuclear talks to leave for Tehran: official

Iranian Foreign Minister Mohammad Javad Zarif is to leave Vienna for Tehran on Sunday night, an Iranian official told Iranian media.

Zarif is supposed to fly to Tehran after the meetings with foreign ministers of the world powers, and would be back to the talks before the June 30 deadline.

Gaps remain in the some areas of the talks, especially the pace and timing of the sanction relief and the monitoring and verification of Iran's nuclear program.

The P5 plus 1 countries (Britain, China, France, Russia and the United States -- plus Germany) are holding meetings to coordinate their positions of the negotiation. French Foreign Minister Laurent Fabius hinted there are also differences among the six countries.

The Iranian official told Iranian media that Iranian delegations will stay in Vienna and continue the talks beyond the June 30 deadline.

"There are some very big challenges to deal with if we are going to get this deal done over the next few days," British foreign chief Philip Hammond told reporters before joining the negotiation in Vienna on Sunday. "There are red lines that we cannot cross and some very difficult decisions, tough choices will have to be made by all of us," he added.

Iran and five United Nations Security Council permanent members plus Germany have been negotiating over the past 14 moths to reach a long-term deal over Tehran's disputed atomic plan. During the period, based on the interim deal made in Geneva in November 2014, Iran would suspend some sensitive nuclear program in return for some sanction relief. Enditem