"The United States will do our part, but ultimately it's up to the Iraqis as a sovereign nation to solve their problems," Obama said from the South Lawn of the White House. He then boarded his Marine helicopter, beginning a four-day trip to North Dakota and California.
The president did not specify what options he was considering but said he would not send American troops back into combat in Iraq. The last U.S. troops withdrew in 2011 after more than eight years of war.
Administration officials said Obama is considering airstrikes using drones or manned aircraft. Other short-term options include an increase in surveillance and intelligence gathering, including satellite coverage and other monitoring efforts.
The U.S. also is likely to increase various forms of aid to Iraq, including money, military training and both lethal and non-lethal equipment.
Obama suggested it could take several days before the administration finalizes its response to the situation on the ground.