Iran pushed back Wednesday against U.S. demands for concessions at nuclear talks, declaring it would never "kneel" over what curbs Tehran must accept to win an end to the sanctions choking its economy.
Both Iran and the six world powers it is negotiating with want an accord by July 20. But they parted last month without significant progress — and came to the table Wednesday with demands that the other side blink first.
"We have never bowed down to imposition and we will not accept it in this round of talks either," Iranian Foreign Minister Mohammad Javad Zarif told reporters in Vienna.
Separately, he warned the West against "pursuing a game of chicken," adding sanctions would never force Tehran to its knees.
Earlier, U.S. State Department spokeswoman Marie Harf said Tehran needs to show "political will to make the choices that we think that they have to make."
British Foreign Secretary William Hague spoke of "significant differences," adding that "achieving an agreement is far from certain."
The six powers are the United States, Russia, China, Britain, France and Germany. Iran's uranium enrichment program is the main dispute, with Tehran resisting U.S.-led attempts to place strict constraints on the process that can produce both reactor fuel and the fissile core of nuclear arms.
Iran says it does not want such weapons and is pushing to keep its present enrichment capacity, while Washington seeks deep cuts in the nearly 20,000 enriching centrifuges that Iran has operating or on standby.
The negotiators now are working on a draft deal they started drawing up in June. Zarif described that document back then as having more blank sections than text.
Associated Press writers Ali Akbar Dareini and Amir Vahdat contributed from Tehran.