UNHCR: Syria 'biggest displacement crisis of all time'
3 September 2013 Last updated at 07:19 BST
More than two million Syrians are now refugees, with the total going up by half a million in the past three months, the United Nations has said.
More than 700,000 have fled to Lebanon, and more Syrians are now displaced than any other nationality.
The UN High Commissioner for Refugees, Antonio Guterres, told the's BBC Imogen Foulkes: "It took two years to reach the first million refugees. It took six months for the second million to be reached.
"It means things are accelerating in a way that represents a dramatic humanitarian problem."