Secretary of State John Kerry has urged Syria's opposition to join next week's peace talks in Switzerland.
The main political opposition group, the Syrian National Coalition, is meeting in Istanbul on Friday to vote on whether to go to the talks.
According to the BBC, Kerry stressed the aim of the so-called Geneva II talks was to begin the process of setting up a transitional government to end the war in Syria.
The three-year conflict has claimed the lives of more than 100,000 people.
Kerry described the 21 January peace conference as the beginning of a process 'that is the best opportunity for the opposition to achieve the goals of the Syrian people and the revolution,' the report added.