Western countries including the US and Britain may be asked to accept tens of thousands of Syrian refugees because the exodus from the civil war is overwhelming countries in the region, the UN's refugee chief has warned.
With no end to the war in sight, the flight of nearly 2 million people from Syria over the past two years is showing every sign of becoming a permanent population shift, like the Palestinian crises of 1948 and 1967, with grave implications for countries such as Lebanon and Jordan, UN and other humanitarian aid officials say.
One in six people in Lebanon are now Syrian refugees. The biggest camp in Jordan has become the country's fourth-largest city. In addition to those who have crossed borders, at least four million Syrians are believed to have been displaced within their own country, meaning that more than a quarter of the population has been uprooted.