Nusa Dua - US Secretary of State John Kerry on Monday urged Iran to come up with new nuclear proposals, rebuffing Tehran's position that the onus is now on foreign powers to unblock the impasse.
Iran's Foreign Minister Mohammad Javad Zarif said on Sunday that the previous foreign offer, made by the "P5+1" group at two meetings in Kazakhstan before the June election of moderate President Hassan Rouhani, was no longer valid.
But Kerry, while welcoming recent overtures including a historic contact between Rouhani and US President Barack Obama, said the ball remained in Iran's court.
"The group of six put a proposal on the table at Almaty and I don't believe as of yet Iran has fully responded to that particular proposal. So I think we are waiting the fullness of the Iranian difference in their approach now," he told reporters in Indonesia.
"So what we need are a set of proposals from Iran that will fully disclose how they will show the world that their programme is peaceful."
The proposals made in the Kazakh capital required Iran to suspend uranium enrichment at the 20% level it says it needs for a medical research reactor, and to halt enrichment at its underground plant at Fordo near the central city of Qom.
EU foreign policy chief Catherine Ashton, who represents the six powers in the talks, said on the sidelines of the UN General Assembly in New York last month that she was still waiting for Iran's response to those previous proposals.
But Zarif said that Rouhani's election had changed the dynamic.
"The previous offer by the P5+1 is history and they should come to the negotiating table with a new approach," the ISNA news agency quoted him as saying on Sunday, while renewing his insistence that a deal could be reached to address the concerns of both sides.
A new round of talks are due in mid-October in Geneva between Iran and the P5+1, comprising the five UN Security Council permanent members - Britain, China, France, Russia and the United States - plus Germany.
They will be the first formal talks held since a phone conversation last month between Rouhani and Obama, the first direct contact between presidents of the two countries since Iran's 1979 Islamic revolution.
"We are encouraged by the outreach," Kerry said.
But he stressed Obama's belief that "it's not words that will make the difference. It is actions that will make the difference".
"And we have made clear that if there are those indicators, the United States and our allies are absolutely prepared to move at an appropriate place to meet their actions. So we are still waiting to see where that comes out."