Two Iranian deputies foreign minister, Abbas Araqchi and Majid Takht Ravanchi, sat with their American counterparts in the Swiss city two days before a plenary session.
Representatives from Iran and the Group 5+1 (the five permanent UN Security Council members plus Germany) are slated to convene on Wednesday.
The new round of negotiations is held at the level of deputies.
This is the first round of talks after the parties decided to extend for more 7 months a self-imposed deadline for signing a comprehensive agreement on Tehran’s civilian nuclear work.
Earlier, Iran’s Foreign Minister Mohammad Javad Zarif had expressed the country’s serious attitude towards the talks with world powers on its peaceful nuclear program and said that reaching an agreement depends on other side’s determination.
Iran and the Group 5+1 (also known as the P5+1 or E3+3) wrapped up a week of intensive nuclear talks in Vienna on November 24 without reaching the long-awaited deal.