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Iranian foreign minister Javad Zarif, left, and Italian foreign minister and the European Union’s foreign policy chief, Federica Mogherini, speak at a joint news conference after a meeting in Rome on Wednesday.
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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, Western diplomats said on Wednesday.

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.

One of the Western diplomats said the first full session of formal negotiations between Iran and the six “power group” nations will take place on Sept. 19 with various preparatory meetings to be held the previous day.

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.

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