VIENNA — Secretary of State John Kerry said on Thursday that the United States would continue to negotiate on a nuclear agreement with Iran that could endure “for decades,” but cautioned that the talks would not be open-ended.
“We will not rush, and we will not be rushed,” Mr. Kerry said, appearing before reporters in front of Vienna’s Coburg Palace, where the negotiations are underway.
A deadline set by a United States law for a 30-day review by Congress is hours away, but Mr. Kerry’s remarks made it all but certain that if an accord is reached here, it will not come on Thursday. Under the same law, missing the deadline would extend the congressional review period to 60 days, allowing a prolonged debate that the White House hoped to avoid.
But Mr. Kerry said that in a discussion Wednesday night with President Obama, they had decided that the strength of a prospective deal, which is meant to guarantee that Iran’s nuclear activities are peaceful, was more important than adhering to a rigid timetable.
“All that we are focused on is the quality of the agreement,” Mr. Kerry said. “If, in the end, we are able to reach a deal, it has to be one that can withstand the test of time. It is not a test of a matter of days or weeks or months. It is a test for decades.”
Mr. Kerry’s wording appeared to suggest a sensitivity to one of the main criticisms of the emerging deal: that it does not constrain Iran’s nuclear capabilities for long enough.
One of the sticking points in recent weeks has been the schedule for Iran’s research and development of more efficient centrifuges to enrich uranium after the first 10 years of the agreement.
That schedule depends on constraints that Energy Secretary Ernest J. Moniz is trying to negotiate with his Iranian counterpart, Ali Akbar Salehi.
Mr. Kerry did not set a deadline, or even a target date, for completing the talks, but he said Mr. Obama was prepared to walk away if progress could not be made.
It was a similar message to the one Mr. Kerry sent on Sunday from the same spot in front of the Coburg.
A senior Obama administration official told reporters this week that the American negotiating team believed there were risks in interrupting the talks, because the Iranian side might be under political pressure at home to back away from elements of a prospective agreement.
“It is pretty darn hard for the Iranians to go home and deal with the politics in Iran,” said the official, who spoke on the condition of anonymity under the ground rules for the briefing. “Everyone understands that once we leave here, we are in less control of what happens in this negotiation. It gets more complicated, not less complicated.”
As Mr. Moniz and Mr. Salehi tried to resolve the final issues Thursday morning, Federica Mogherini, the foreign policy chief for the European Union, convened a separate session with Mr. Kerry and senior diplomats from Britain, China, France, Germany and Russia, the five other world powers that are taking part in the negotiations.
The foreign ministers of China and Russia are the only top diplomats among the six world powers negotiating with Iran who are not in Vienna, but they are expected to return if an accord is reached.
This article was written by Michael R. Gordon & David E. Sanger for The New York Times on July 9, 2015. David E. Sanger is chief Washington correspondent of The New York Times. Mr. Sanger has reported from New York, Tokyo and Washington, covering a wide variety of issues surrounding foreign policy, globalization, nuclear proliferation and Asian affairs.