Early 2003

The United States prepares to lead the invasion of Iraq. The United States and others position personnel and supplies in the region to respond to a possible refugee crisis.

March 19, 2003

President George W. Bush announces the start of combat. Troops enter Baghdad in April; Bush announces the end of major combat operations May 1. Aid workers assist the return of Iraqis exiled during the rule of Saddam Hussein.

2003-2006

Attacks on U.S. and Iraqi troops and civilians continue; security deteriorates.

Feb. 22, 2006

The bombing of a Shiite shrine in Samarra fuels new levels of sectarian violence, triggering the exodus of Iraqis to Syria, Jordan and other neighbors.

November 2006

One hundred thousand Iraqis are fleeing every month, the U.N. High Commissioner for Refugees reports. Refugee populations are estimated at 1 million in Syria, 750,000 in Jordan and 150,000 in Egypt. More than 2 million are displaced inside Iraq.

Nov. 23, 2006

Coordinated car bombings in Sadr City kill at least 215 and wound more than 250 in the deadliest attacks since the invasion.

December 2006

Jordan closes its borders to most Iraqis. The Iraq Study Group warns that growing displacements threaten regional stability. Kirk W. Johnson, a former reconstruction coordinator for the U.S. Agency for International Development in Fallujah, begins a list of Iraqis seeking resettlement after being targeted for working with the United States.

Jan. 10, 2007

Bush announces a surge of 20,000 additional troops to reverse growing violence in Iraq.

Jan. 16, 2007

In Baghdad, the U.N. Assistance Mission to Iraq reports that more than 34,000 civilians were killed in 2006. In Washington, the Senate Judiciary Committee hears testimony from Iraqis attacked for working with the United States. Ellen Sauerbrey, assistant secretary of state for population, refugees and migration, tells the panel that the refugee crisis is "the very top priority for my bureau," and that Iraqis could use the "overwhelming majority" of 20,000 open resettlement slots for the year.

Feb. 3, 2007