US President Barack Obama has told the Iranian people that a deal to transform the relationship between the two countries could be within reach.
“We have the best opportunity in decades to pursue a different future between our countries,” he said in a video message for Persian New Year.
Six world powers are negotiating a deal aimed at limiting Iran’s nuclear activity, with a March deadline near.
The president conceded there were still “gaps” in negotiations but was hopeful.
Iran’s Foreign Minister Mohammad Javad Zarif said in an apparent response to Mr Obama’s video it was time for the US and other negotiating countries – China, France, Germany, Russia and UK – to move forward with an agreement.
“Iranians have already made their choice: Engage with dignity. It’s high time for the US and its allies to choose: pressure or agreement,” Mr Zarif wrote in a message posted on his official Twitter account.
On Friday, US Secretary of State John Kerry and Mr Zarif met for the fifth consecutive day of talks in Switzerland.
If Iran’s leaders agreed to a reasonable deal, then the country would be on a path to prosperity, Mr Obama said.
“I believe that our nations have an historic opportunity to resolve this issue peacefully – an opportunity we should not miss,” Mr Obama said in his message celebrating Nowruz.
Isolation awaited if agreement was not reached, he added.
But the president has yet to convince the US Congress of the merits of a deal, and many lawmakers remain opposed to the easing of sanctions.