Syria's foreign-based political opposition on Friday rejected any role for Bashar Assad in a transitional government, after Western powers appeared to soften their stance towards the Syrian president.
Diplomatic moves on Syria have been overtaken by an escalation of the war on the ground, after Russia launched air strikes inside Syria in support of its ally Assad this week.
British Prime Minister David Cameron was quoted last week as saying Assad could stay on as part of a transitional government but should not be part of Syria's future in the long run.
Those comments came after US Secretary of State John Kerry said Assad had to go, but not necessarily "on day one."
After Russia's intervention, which fighting groups have said will only prolong the war, the Syrian National Coalition reiterated its position that Assad must be excluded from any political process.
Any such process must "prevent the reproduction of the current regime with a new face, and must not give any role in a transitional process or in the long term" to Assad or those around him, it said in a statement.
The four-year-old Syrian conflict has killed an estimated 250,000 people.