The United Nations is leading a new appeal to help those who have fled the violence in Iraq.
Its refugee agency, the UNHCR, estimated that some 50,000 people leave the country every month.
Syria and Jordan have accepted almost two million refugees, with another two million reported to be displaced within Iraq itself.
On the eve of an international conference in Geneva, the head of the UNHCR, Antonio Guterres, insisted that wealthy countries such as the US were not doing enough to tackle the problem.
