"The United States and the international community can best help displaced Iraqis by quelling the violence in Iraq," Paula Dobriansky, the US under-secretary of state said at a news conference with Antonio Guterres, the UN high commissioner for refugees.
"At the same time, we have a responsibility to respond to the immediate needs of Iraqis who have fled violence and persecution," she said,
The US has accepted 466 Iraqi refugees since 2003, triggering congressional criticism that it had not done enough.
The state department said last week that it had created a task force to ensure the country was doing "its share".
The UNHCR estimates that up to 2 million Iraqis have moved to neighbouring countries, mainly Syria and Jordan, before and since the 2003 invasion of Iraq.
An additional 1.7 million Iraqis are believed to be internally displaced.