Representatives from Iran, Russia, and Turkey met in Moscow last week for talks on Syria. Strangely, there were no Syrians at the meeting. In Tehran, political analyst Mosayyeb Naimi said one concern is Turkey's ability to sell a ceasefire to armed rebel groups.

"The level of Turkey's ability to convince armed rebel groups to accept the ceasefire is unknown, particularly because Turkey is in conflict with some of those groups," said Mosayyeb Naimi, political analyst.

"The situation is not like one group is the same as others. And differences among various groups are a problem for the next phase of the plan."