One in eight of Iraqis have now left their homes, with up to 50,000 people leaving each month, the UNHCR said.

It said the exodus was the largest long-term movement since the displacement of the Palestinians after the creation of Israel in 1948.

"The longer this conflict goes on, the more difficult it becomes for the hundreds of thousands of people displaced," UNHCR head Antonio Guterres said.

The UNHCR estimates that the number of Iraqis living beyond the country's borders as refugees stands at 2 million and a further 1.7 million live within the borders as displaced people. But it warns the number of internally displaced - those forced to leave their homes but not the country - could reach 2.7 million by the end of the year.

Syria, Jordan, Egypt and Lebanon are hosting most of the country's refugees. Many of these refugees live in conditions of acute poverty and the agency says that there is growing evidence of women turning to prostitution.

The agency has also urged neighbouring countries who are hosting refugees to keep their borders open because Iraq's continuing violence will fuel further floods of refugees.

BBC/VOVNews