Iran and world powers have reportedly agreed on a framework and timetable for negotiations on a comprehensive deal, to contain the military threat posed by Tehran's nuclear program.
The world powers including the US, UK, France, China and Russia plus Germany, also referred to as P5+1, ensured that Iran cut back uranium enrichment in return for partial sanctions relief.
Deputy Foreign Minister Abbas Araqchi said that there was a positive atmosphere at the summit in Vienna.
EU foreign policy chief Catherine Ashton said representatives identified the issues that needed to be resolved, But cautioned that there was a lot to do and it would not be easy to build on November's interim agreement, the BBC reported.
The world powers want Iran to roll back its nuclear infrastructure in order to make sure that the country doesn't engage in assembling a nuclear weapon.
Meanwhile, Iran has said that it will continue with its "peaceful" nuclear work and demanded an end to the sanctions that are affecting its economy.