Iran's President Hassan Rouhani has said that world powers must "seize the opportunity" of a landmark nuclear deal, insisting Tehran had taken the "necessary steps" for an accord.
Rouhani's remarks on Tuesday appeared to be a response to US President Barack Obama, who on Monday said: "The issues now are - does Iran have the political will and the desire to get a deal done?"
Speaking in Tehran, Rouhani said that although gaps remain between Iran and the P5+1 powers - Britain, China, France, Russia and the US plus Germany - it was up to them to close a deal.
"Right now good progress has been made although we are some distance away from the final agreement," he said during a meeting with India's national security adviser, Ajit Rouhani.
"Iran has taken necessary steps and now it's the other side's turn to seize the opportunity," he added.
Two deadlines for a permanent agreement on Iran's controversial nuclear programme have already been missed, requiring the talks to be extended.
Negotiators are now working towards the political outline of a deal by March 31, with the cut-off point for the technical details of a comprehensive accord by June 30.
Disagreements centre on the extent of nuclear activities Iran will be allowed to continue and the timetable for the lifting of sanctions.
At a speech later on Tuesday to mark the 36th anniversary of the Islamic revolution, Rouhani told foreign diplomats Iran still believed in a "win-win solution" in the talks.
"In recent months we have shown the flexibility necessary to resolve this political issue," he said. "We hope that the other negotiating party can show more than before. If so ... in a short time the disputes can be resolved."
Iran's supreme leader Ayatollah Ali Khamenei, whose authority overrides Rouhani and as such he will have the final word on the nuclear issue, said Sunday he would rather see the talks fail than reach a "bad deal".
"The Americans keep reiterating that it's better to have no deal than a bad one. I fully agree with that," Khamenei said.
Both the US and Iran have said in recent days they are against further time being added to negotiations.
In his remarks on Monday, Obama said: "I don't see a further extension being useful if they have not agreed to the basic formulation and the bottom line that the world requires to have confidence that they're not pursuing a nuclear weapon."
Iran denies seeking an atomic bomb and says its nuclear programme is for peaceful energy purposes only.