Back-to-back meetings between nuclear negotiators in Vienna have pushed Iran talks to the final day, after three deadline extensions in as many weeks.
With no announcements made, U.S. and European diplomats worked through dinner late Sunday in an effort to resolve what a senior U.S. State Department official warned earlier in the day were "major issues" to be resolved in the talks.
Earlier in the evening, Iranian Foreign Minister Mohammad Javad Zarif shouted to reporters from the balcony of the Palais Coburg, "We still have work.”
Iranian official Alireza Miryousefi said a Sunday announcement of the 100-page agreement would be “simply logistically impossible.”
The Associated Press first reported that an announcement would be made Monday.
Among other disagreements, the sides were reported split last week over a U.N. arms embargo on Iran, which Western powers want to keep in place.
Lavrov returns to Vienna
In the last few days, the arrivals and departures of the top diplomats at the Palais Coburg have been a barometer for speculation on the finality of the deal.
With a little more than 24 hours to go on the latest deadline, Russian Foreign Minister Sergei Lavrov landed Sunday afternoon to rejoin the closed-door discussions on whether economic sanctions on Iran will be lifted in exchange for limitations on Tehran’s nuclear program.
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“I think we're getting to some real decisions. So I will say, because we have a few tough things to do, I remain hopeful,” U.S. Secretary of State John Kerry said Sunday morning. The outcome of a meeting with Iranian Foreign Minister Zarif a day earlier was “positive,” he added.
Outside the Palais Coburg, French Foreign Minister Laurent Fabius briefly spoke with reporters before a meeting with the head of the International Atomic Energy Agency.
"I hope we are entering the final phase of this marathon negotiation," Fabius told reporters. With a new self-imposed deadline set to expire July 13, no official schedule for an announcement has been set.
EU foreign policy chief Federica Mogherini, who also is part of the talks, said Sunday morning negotiators were in the "decisive hours."
Firm actions, words in Iran
Meanwhile, Iranian President Hassan Rouhani on Sunday ordered the enforcement of a law that overlaps with several areas that likely would be covered by a potential deal, Iran state news agency IRNA reported.
The legislation, which passed in June, in part, would restrict oversight access to military sites and nuclear scientists - a point of contention during this latest round of talks.
Iran's supreme leader, Ayatollah Ali Khamenei, called Saturday for the struggle against the U.S. to continue, in comments suggesting that Tehran's distrust of Washington will persist no matter what the outcome of the talks.
Iran's state-run Press TV cited Khamenei as calling the U.S. an "excellent example of arrogance." It said Khamenei told university students in Tehran to be "prepared to continue the struggle against arrogant powers."