ALL ABOUT THE SANCTIONS:

An understanding is emerging between Iran and six major powers that a final nuclear deal between the two sides must be structured around a key demand of the U.S. and its European partners: that Tehran stay at least a year away from amassing enough fuel for a nuclear weapon, according to people familiar with the negotiations. [...]

[I]n recent weeks, people familiar with the talks say that Iran's position is shifting. While there is no explicit agreement on the 12-month breakout period, officials say there is a growing understanding on all sides that it must be part of a deal.

Critically, some officials say, Iran has also accepted that in order to achieve that, it will have to agree to a reduction in the nearly 10,000 centrifuges it now operates and cut its enriched-uranium production.

The narrowing of gaps on this principle, and other potential compromises, have helped encourage a shift in sentiment among diplomats in recent weeks that a nuclear deal is finally possible after more than a decade of talks.

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