Talks backed by Russia, Turkey and Iran between Syrian rebel factions and government representatives opened on Monday morning in Kazakhstan.
The talks are the first time the opposition and representatives of Syrian President Bashar Assad have come together since United Nations-brokered negotiations in Geneva were suspended in early 2016.
The negotations are expected to focus on consolidating a shaky cease-fire that has been in place since December 30.
According to Iran, reserving the truce will be "the most important issue" in the talks. The country's Foreign Ministry spokesman said Tehran is hopeful that the event can also pave the way for the delivery of humanitarian aid.
Representatives of both Syria's opposition and Assad appeared at the opening ceremony of the talks at the luxury Rixos Hotel in Kazakhstan's capital. But the rebels did not plan to meet the other side face to face, a source told Reuters.
Adding to the difficulties, Russia and Turkey remain at odds over fundamental issues such as whether Assad should stay in power or step down for the sake of reconciliation.
The talks notably exclude the West, although Moscow extended a last-minute invitation to the new United States administration last week.
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