"The Syrian negotiation commission of revolutionary and opposition forces declares boycott of the congress in Sochi called by Russia for January 29-30," the High Negotiations Committee tweeted.
The goal of the gathering is to bring together opposition and pro-government forces as well as representatives of Syria's numerous ethnic and religious groups. The congress lets the participators discuss their vision of Syria's future in a bid to advance the peace process.
Meanwhile, UN Special Envoy for Syria Staffan de Mistura said that he had inquired about UN presence at the peace conference with UN Secretary-General António Guterres. Moscow said it expects the UN chief to respond positively to observer role at the congress.