The U.N. special envoy for Syria warned Monday many thousands more refugees would flee to Europe if the international community cannot find a peace accord and abandons them to the Islamic State group.
"Why are people leaving? Because they have lost hope after five years of endless conflict and they see only one winner, Daesh," Staffan de Mistura told journalists in Brussels, using another term for IS.
De Mistura said up to one million more people could be at risk in western Syria, potentially adding to the flood of refugees seeking safety in the European Union.
The international community was constantly trying but failing to come up with a formula but "there is no more time for such lengthy political processes," he said.
In failing to sink their differences, mainly over the future governance of Syria and the role of President Bashar al-Assad, world powers were by default supporting a military solution to a conflict which has now claimed nearly 250,000 lives, he said.
Some 11 million Syrians have been displaced from their homes by the conflict that began in March 2011, with four million becoming refugees.
"It is time to find a solution ... otherwise there will not be any Syrians left."
IS gains "should make everyone wake up; they are only a few miles (kilometers) from Damascus. Iran, Saudi Arabia, Turkey, Russia -- Daesh should be worrying them all," he added.
Repeated U.S. and Russian efforts to find a peaceful solution in Syria have failed and as de Mistura described, the outlook was less than encouraging.
Earlier Monday, Moscow dismissed U.S. concerns of a Russian military buildup in Syria, saying its military aid to long-time ally Assad was perfectly normal.
De Mistura declined to comment on the issue.