Speaking to reporters in Luxembourg on Monday, Zarif said he has met his counterparts from Britain, France and Germany to discuss “how to expedite the talks in the few tough days ahead.”

Zarif travelled to Luxemburg on Monday to meet with Britain's Philip Hammond, Germany's Frank-Walter Steinmeier, France's Laurent Fabius and the European Union's foreign policy chief Federica Mogherini to discuss the latest status of nuclear negotiations.

Iran and the Group 5+1 (Russia, China, the US, Britain, France and Germany) are negotiating to hammer out a lasting accord that would end more than a decade of impasse over Tehran's civilian nuclear program.

Elsewhere in his comments, Zarif said the talks on drafting the text of a nuclear deal will go on and foreign ministers will also join the negotiations if necessary.

“I don’t know how many days it will take to finish this… if there is political will to accept the facts and move ahead on the basis of what we have agreed in Lausanne, there will be a good possibility to finish the negotiations until the deadline or a few days afterwards,” Zarif explained.

On April 2, Iran and the Group 5+1 (also known as the P5+1 or E3+3) reached a framework nuclear agreement in Lausanne, Switzerland, with both sides committed to push for a final deal until the end of June.