They met on the sidelines of the 10th International Conference on Syrian Peace in the Russian resort city of Sochi on Monday.
Earlier, Iran’s senior official also sat down for talks with Russian President's Special Envoy for Syria Alexander Lavrentiev and Deputy Foreign Minister Sergey Vershinin.
First day of Sochi talks were held behind closed doors and De Mistura said after the meeting that today preliminary talks were held and establishment of Syria Constitution Committee is to be dealt with.
General summit of Sochi is slated for Tuesday and Iranian and Russian delegations are to take part in it.
Syrian new constitution, humanitarian issues such as return of refugees and freedom of prisoners and detainees are on the Sochi meeting’s agenda.
The guarantor states of ceasefire agreed to hold counseling meetings on the activities of the Constitution Committee with the UN and belligerent sides’ representatives.
The ninth round of Astana Talks to solve Syrian crisis was held in Astana on May 15.
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