Zarif, who is also the country's chief nuclear negotiator, is now in Luxembourg, where he met his counterparts from Britain, France and Germany to discuss "how to expedite the talks in the few tough days ahead."
Meanwhile, Russian Deputy Foreign Minister Sergei Ryabkov has announced that the foreign ministers of Iran and the Group 5+1 (Russia, China, the US, Britain, France and Germany) will hold a meeting between June 25 and 30.
Zarif's trip to Vienna will come as his deputies, Seyed Abbas Araqchi and Majid Takht Ravanchi, have started the eighth round of talks since June 17.
In the latest round of negotiations, the two Iranian diplomats held a meeting with EU's Deputy Foreign Policy Chief Helga Maria Schmid on Wednesday afternoon.
Earlier on Wednesday, media reports said that Zarif and US secretary of State John Kerry plan to hold talks in Vienna in the coming days.
The next couple of days are going to be very tough, Zarif had said earlier on Monday in reference to the nuclear talks between Iran and the sextet.
Iran and the Group 5+1 (also known as the P5+1 or E3+3) are negotiating to hammer out a lasting accord that would end more than a decade of impasse over Tehran's civilian nuclear program.
On April 2, the two sides reached a framework nuclear agreement in Lausanne, Switzerland, with both sides committed to push for a final deal until the end of June.