U.S. Secretary of State John Kerry arrived in Geneva on Tuesday to meet his Iranian counterpart as global powers seek to accelerate talks to reach a deal on reining in Iran's nuclear program, reports AFP.
Kerry has said the aim of his talks with Zarif on Wednesday is to "take stock" and provide guidance for their negotiating teams ahead of fresh discussions by global powers known as the P5+1 due to resume on Sunday.
Zarif said on Sunday that his talks with Kerry would explore ways to give impetus to nuclear talks.
Tehran and the so-called P5+1 group of nations have been locked in talks since February on a permanent nuclear deal aimed at ending a decade-long diplomatic crisis.
Despite making progress, the two sides failed to clinch a definitive deal by a November deadline and agreed to extend the talks for another seven months.
Another inconclusive round of negotiations was held in Geneva between Iranian officials and the six powers in December. Iran’s deputy foreign minister, Abbas Araqchi, said following those talks that they had been "very useful and helpful".
Diplomats fear that time may be running out, after two earlier deadlines for an accord were missed.
American lawmakers are eager to impose new sanctions on Iran as the Obama administration has sought to hold them off, warning it could scuttle all hopes of a deal.
Washington's UN envoy Samantha Power said Monday that ratcheting up sanctions against Iran would likely torpedo the negotiations.
"Imposing new sanctions will almost certainly end a negotiations process that has not only frozen the advance of Iran's nuclear program, but that could lead us to an understanding that would give us confidence in its exclusively peaceful nature," Power told a think-tank, according to AFP.
"If we pull the trigger on new nuclear-related sanctions now, we will go from isolating Iran to isolating ourselves," she said.
Under an interim deal agreed in November 2013, Iran's stock of fissile material has been diluted from 20 percent enriched uranium to five percent, in exchange for limited sanctions relief.
Kerry has said that the United States hopes to see an outline accord in March, perhaps leaving some of the complex technical aspects to be hammered out by the teams ahead of the end of June.