A new round of talks to seal a comprehensive nuclear deal between Iran and six major world powers will start Sept. 18 in New York, a Western diplomat said Wednesday, The Wall Street Journal reported.
The two sides had said negotiations would resume ahead of the U.N. General Assembly meeting in New York. For the past six months, the talks have taken place in Vienna.
Iran and the six-nation group-the U.S., the U.K., France, Germany, China and Russia-are seeking to reach a comprehensive nuclear deal by Nov. 24 that would offer Tehran a time frame for reducing sanctions in exchange by Iran to curtail their future nuclear activities.
The deadline was extended by four months after the two sides failed to reach a final deal by the original July 20 target date.
Last year's General Assembly meeting proved a watershed in the nuclear talks, with U.S. Secretary of State John Kerry sitting down with his Iranian counterpart and President Barack Obama holding a historic 15-minute phone call with his Iranian counterpart, Hasan Rouhani.
Those overtures led in November to an interim agreement that essentially froze Iran's nuclear work in return for modest sanctions relief.
On Monday, Iranian Foreign Minister Javad Zarif said he remains "quite optimistic" the two sides can reach a deal following talks he held that day with Catherine Ashton, the European Union's foreign policy chief. Baroness Ashton chairs the six-nation group.
"I am quite optimistic after discussions with Lady Ashton that we can in fact resolve this issue in time," he said.
However, there are significant challenges facing the negotiators including deep divisions between Iran and the U.S. over the scale of Tehran's future nuclear enrichment activities. The growing tensions between Russia and its Western partners in the six-nation group could also significantly complicate the talks.
There are also growing concerns in Western capitals about the pace of discussions between Iran and the U.N.'s atomic agency over Tehran's past nuclear activities that the West suspects were aimed at developing a nuclear weapon.
Iran has denied that it has sought to or is seeking to build nuclear weapons.
The International Atomic Energy Agency is due to send a report to member states on Thursday or Friday that diplomats say could warn of stalled progress in the talks with Tehran on Iran's past nuclear work. The IAEA has listed more than a dozen issues it wants to pursue with Iran but so far there have only been meaningful discussions on one of those, three Western diplomats said this week.
U.S. and European officials have warned publicly that a failure by Iran to detail its past nuclear activities could jeopardize the comprehensive nuclear deal.
Iran has also bristled at a U.S. decision on Friday to impose a range of sanctions on Iranian firms and individuals.
They include a bank that provides U.S. dollar bills to the Iranian government; a group that helped Iran evade sanctions on oil and petrochemicals; and several transportation firms, the U.S. Treasury and State departments said.
Iran says the steps breach the spirit of last November's interim nuclear deal. Washington says it has always made clear it will continue to strictly enforce existing sanctions.