The U.S. officials would not describe Netanyahu's reaction. But the next day, he delivered his General Assembly speech, blasting Rouhani as a "wolf in sheep's clothing" and warning the U.S. against mistaking a change in Iran's tone with an actual change in nuclear ambitions. The Israeli leader has subsequently denounced the potential nuclear agreement as the "deal of the century" for Iran.
America's negotiating partners were then informed, though European officials said they assumed something was cooking between Washington and Tehran based on the surprising progress toward a deal after more than a decade of stalemate.
The secrecy of Obama's effort may explain some of the tensions between the U.S. and France, which earlier this month balked at the proposed accord, and with Israel, which is furious about the agreement and has angrily denounced the diplomatic outreach to Tehran.
Burns and Sullivan continued their efforts behind the scenes at this month's larger formal negotiations between world powers and Iran in Geneva, though the State Department went to great lengths to conceal their involvement.
Their names were left off of the official delegation list. They were housed at a different hotel than the rest of the U.S. delegation, used back entrances to come and go from meeting venues and were whisked into negotiating sessions from service elevators or unused corridors only after photographers left.
Congress hasn't been notified in detail about the secret diplomacy. That could also pose a challenge for Obama, who has been waging a tense battle with Republicans and Democrats alike to prevent them from enacting new sanctions against Iran at the same time he has been offering Tehran some relief.
Several lawmakers from both parties openly scoffed Sunday at the terms of the deal between world powers and Iran. And in a reflection of the primary role played by his administration, some already are referring to the end result as Obama's agreement. None said they had been briefed on the secret talks.
"I don't know how to react," Sen. Bob Corker, the Senate Foreign Relations Committee's top Republican, said on "Fox News Sunday." ''The administration has been trying to set the framework for these discussions for some time and I guess I'm not really particularly shocked that this has occurred."
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