Obama, in his first comments on the deteriorating situation, said it was clear Iraq needed additional assistance from the U.S. and international community given the lightning gains by the militant group Islamic State of Iraq and Levant. Republican lawmakers pinned some of the blame for the escalating violence on Obama's reluctance to re-engage in a conflict he long opposed.
For more than a year, the Iraqi government has been pleading with the U.S. for additional help to combat the insurgency, which has been fueled by the civil war in neighboring Syria. Northern Iraq has become a way station for insurgents who routinely travel between the two countries and are spreading the Syrian war's violence.
Iraqi leaders made a fresh request earlier this week, asking for a mix of drones and manned aircraft that could be used for both surveillance and active missions. Officials said Obama was considering those requests and was expected to decide on a course of action within a few days.
The U.S. already is flying unmanned aircraft over Iraq for intelligence purposes, an official said.
Short of airstrikes, the president could step up the flow of military assistance to the beleaguered Iraqi government, increase training exercises for the country's security forces and help boost Iraq's intelligence capabilities. The U.S. has been leery of its lethal aid falling into the hands of militants or being otherwise misused.
State Department spokeswoman Jen Psaki said the U.S. is sending about $12 million in humanitarian aid to help nearly a million Iraqis who have been forced from their homes by recent fighting.
Vice President Joe Biden discussed the deteriorating security situation Thursday with Iraqi Prime Minister Nouri al-Maliki. The White House said Biden underscored that while the U.S. stands ready to help, it would be crucial for Iraq to come up with longer-term solutions to its internal political strife.
Nearly all American troops left Iraq in December 2011 after Washington and Baghdad failed to negotiate a security agreement that would have kept a limited number of U.S. forces in the country for a few more years at least.
Sen. John McCain, R-Ariz., a frequent White House critic, called on Thursday for Obama's entire national security team to resign. House Speaker John Boehner, R-Ohio, accused the president of "taking a nap" while conditions worsened.
But Congress appeared divided over how to respond, with some Republicans backing airstrikes and other lawmakers from both parties suggesting that was the wrong approach.
There were no calls for putting American troops back on the ground in Iraq, and Obama's advisers said the president had no desire to plunge the U.S. back into a conflict there.
"The president is mindful that the United States has sacrificed a lot in Iraq and we need to not just be taking this all back on ourselves," said Ben Rhodes, Obama's deputy national security adviser. "We need to come up with solutions that can enable the Iraqis to manage their internal security and their internal politics."
Even after American troops left Iraq, the U.S. has continued to send weapons and ammunition although not nearly as much as Baghdad has requested. A U.S. training mission for Iraqi counterterror forces dwindled to almost nothing earlier this year, and Baghdad asked as early as last summer for armed U.S. drones to track and strike terrorist hideouts.
The administration resisted, and similarly rejected options for airstrikes in neighboring Syria.
Instead, the U.S. Embassy has sold small scout helicopters, tanks, guns, rockets and at least 300 Hellfire missiles to Iraqi forces. A U.S. shipment of ScanEagle surveillance drones is to be delivered to Iraq later this summer, and the State Department is trying to speed an order of Apache helicopters to Baghdad. Additionally, Congress is reviewing a $1 billion order of arms, including Humvee vehicles, to Iraq.
Several thousand Americans also remain in Iraq, mostly contractors who work at the U.S. Embassy in Baghdad on programs to train Iraqi forces on American military equipment like fighter jets and tanks. One of the largest training missions was based at the air base in the city of Balad, about an hour northwest of Baghdad, where three planeloads of Americans were being evacuated on Thursday. They included 12 U.S. government officials and military personnel who have been training Iraqi forces to use fighter jets and surveillance drones.