In a press conference in Geneva, de Mistura said that Tehran meeting was not political but an expert-level meeting as the guarantor countries have worked actively with the United Nations to strengthen the cessation of hostilities agreement and prepare for the next Astana meeting, considering the upcoming meeting in Astana as "good and contributor".
He pointed out that there was some sort of movement on the issue of the besieged and detained persons and the issue of mine clearance.
He announced that he would hold talks with Russian Deputy Foreign Minister Gennady Gatilov in Geneva on Monday and that the United States had declined to take part in any trilateral meeting for now.
"The trilateral meeting that as you know was a possibility is being postponed, it is not taking place on Monday. It will be a bilateral. But the trilateral is not off the table, just being postponed," de Mistura added.
"There is a clearly an intention to maintain and resume these trilateral discussions, the date and circumstances were not conducive for this to happen on Monday." He said answering a question about the U.S. administration intent to participate in the trilateral meeting.