Secretary of Defense Chuck Hagel says three days of airstrikes against Islamic State militants in northern Iraq have been "very effective."
Hagel said during a visit Monday in Australia that the United States will consider further requests for help from the Iraqi government.
"We're going to continue to support the Iraqi security forces in every way that we can as they request assistance there and we will again build partnerships as we are now, recognizing the threat not just to the United States but to the civilized world," Hagel said.
U.S. forces are attempting to blunt an offensive by the extremist Islamic State group that threatens to overrun Irbil, the capital of Iraq's semi-autonomous Kurdish region.
Hagel said Monday that Australia, Britain and France are working with the U.S. to supply humanitarian aid for the thousands of displaced Christians, Yazidis and other religious minorities trapped in the area.
"This is a humanitarian issue of great consequence for all of the world, and I think great powers understand they have responsibilities in these areas," he said.
Late Sunday, the State Department said it has temporarily removed some staff from the U.S. consulate in Irbil.
A statement said some of the personnel were dispatched to the southern city of Basra, and others to the Jordanian capital, Amman. It said the move was made "out of an abundance of caution rather than any one specific threat."
The International Organization for Migration says the number of internally displaced people in Iraq now totals more than 1 million.