Ali-Akbar Salehi, head of Iran's Atomic Energy Organization, is heading to Lausanne, Switzerland as part of a negotiating team led by Foreign Minister Mohammad Javad Zarif.
The negotiators are working to meet a self-imposed deadline for a preliminary agreement by the end of March. The talks are focused on an agreement to limit Iran's nuclear program in exchange for the lifting of harsh international economic sanctions.
IRNA quoted Salehi as saying that Tehran is seeking a win-win agreement, while Zarif has stated that a full lifting of all sanctions is a red-line condition for any deal.
Iran and the so-called P5+1 the U.S., Russia, China, Britain, France and Germany hope to reach a rough deal on the nuclear program by the end of March and a final agreement by June 30.