Iran, the United States and a number of European countries ended the second round of trilateral talks in Geneva on Friday, IRNA reported.
The negotiations took about two hours and a half.
This round of talks were held in the deputy foreign ministerial level between Iran and the US with Helga Schmid, a deputy to the European Union Foreign Policy Chief Federica Mogherin also attending.
The three are to continue their talks on Saturday as well.
On Sunday, Iran's Minister of Foreign Affairs Mohammad Javad Zarif is to joining his American counterpart John Kerry in Geneva to continue negotiations.
The US and Iranian experts held about five hours of discussions on Friday morning as well.
Deputy foreign ministers of other member states of the 5+1 are likely to join them on the fourth day of talks.