In a report released on the eve of the seventh anniversary of the US-led invasion of Iraq, Refugees International said 33 percent -- or 500,000 people -- of the 1.5 million internally displaced people forced from their homes in 2006 and 2007 "live as squatters in slum areas."

To view the report in full, visit Refugees International.

To compile the report, the group's staff visited 20 squatter camps around Iraq, all lacking basic services like water and sanitation, and often built in precarious places -- under bridges, alongside railroad tracks and atop garbage dumps.

The Iraqi government is doing little, if anything, to help the displaced, the report said, urging the United States to step in and take up the slack because it "bears special responsibility" for the looming humanitarian crisis.

"Though Iraq is well positioned to generate vast sums of revenue from its oil, it will take many years before the government is able to rebuild the country's infrastructure and provide basic services to its people," the report said.

"Ongoing political and security concerns continue to challenge development efforts. It is thus critical that the US and other donors continue to support a strong and expanded humanitarian program, working hand-in-hand with a variety of community development initiatives."

In a Refugees International video clip of some of the camps, children played in front of their family "home" -- a rectangle of rusted jerrycans and breeze-blocks, with no roof.

The landscape bore a grim resemblance to Port-au-Prince after a powerful earthquake devastated the Haitian capital in January, and seemed a far cry from images some are used to seeing of Iraq's bustling markets and busy streets dotted with US and Iraqi military camouflage uniforms.

A man with a long white beard and glasses challenged the cameraman to find the front door of his ramshackle home in the Iraqi camp for displaced people.

"There is no door," the man said.

"This place isn't fit for animals."

During an event unveiling the report in Washington, Iraq's Ambassador to the United States Samir Sumaidaie said his government needed to do more to help the masses of displaced Iraqis inside and out of the country.

"A country built on a lake of oil shouldn't have its people in these conditions," he said after watching the group's presentation.

Although Iraq's war violence now rarely makes headlines in US newspapers or dominates television screens, Americans must not lose sight of the "injustice and violence that face the displaced men, women and children in Iraq," she said.

Women and girls have been hit particularly hard by the refugee crisis, Jordan's Queen Noor said.

When refugee families run out of money, they sometimes send out their young daughters to work as prostitutes.

"If you know anything about our culture, you'll know how desperate a situation they are in to do this," said the widow of Jordan's King Hussein, urging the United States and other donor countries to help Iraq or risk the dangerous refugee situation further destabilizing an already volatile Middle East region.

"It is vitally important to understand that this is global humanitarian and security issue," Noor said.

Middle East Online