VIENNA — U.S. Secretary of State John Kerry threatened Thursday to walk away from nuclear talks as he signaled that diplomats won't conclude an agreement with Iran over the coming hours — another delay that this time could complicate American efforts to quickly implement any deal. The Iranians immediately fired back, accusing the United States and its European allies of causing the deadlock.
Kerry and other Western officials said Iran still hadn't made the tough political decision to roll back its nuclear program. But a senior Iranian official said it was the Americans and their partners who were backtracking on several key commitments related to Iran's permitted level of nuclear activity and definitively ending economic sanctions against Tehran.
"This is not open-ended," Kerry told reporters outside the 19th century Viennese palace hosting the negotiations. "We can't wait forever for the decision to be made. If the tough decisions don't get made, we are absolutely prepared to call an end to this process."
It was the strongest indication yet of U.S. frustration with Iran, and vice versa, coming two days after President Barack Obama vowed a similar response to Iranian intransigence and suggesting patience was running out as the current round of talks headed into its 14th day.
Thursday's latest delay for a comprehensive deal is significant. Iran is demanding prompt easing of economic penalties for nuclear concessions, and the longer it takes world powers to make good on their promises, the longer they'll have to wait for the Iranians to scale back their nuclear program.
"We will not rush, and we will not be rushed," Kerry said.
Kerry spoke after discussing the state-of-play with other world powers Thursday evening.