Optimism for revised accord following 16 months of negotiations.
Diplomats say they believe they are close to restoring the Iran nuclear deal, four years after the United States pulled out.
For the past 16 months, negotiators from Washington and Tehran have been working with the other signatories to reestablish the accord.
The European Union laid down what it called its final offer earlier this month.
Few details have been officially made public, but sources have told Al Jazeera the new deal will be rolled out in four phases across two 60-day periods.
The EU’s foreign policy chief says Tehran has given what he calls a “reasonable” response to the proposal.
All sides are waiting for the US to reply.
So what are the final hurdles to a new agreement?
Presenter: Laura Kyle
Mohammad Marandi – Adviser to the Iranian negotiation team
Hamidreza Azizi – Visiting fellow, German Institute for International and Security Affairs
Alex Vatanka – Director and senior fellow, The Middle East Institute