Updated at 12:46 p.m. ET
President Obama has ruled out the use of ground troops in Iraq, saying any action will be "targeted and precise" but must be accompanied by political action by Iraqis to end sectarian divisions.
"We will not be sending U.S. troops back into combat in Iraq, but I have asked my national security team to prepare a range of other options that could help support Iraq's security forces," Obama said from the south lawn of the White House.
Iraqi forces have offered little opposition to advancing members of the Islamic State of Iraq and Syria, a Sunni extremist group. ISIS has seized the key cities of Mosul and Tikrit, both predominantly Sunni, and also towns in the more ethnically diverse Diyalah province.
"This poses a danger to Iraq and its people, and, given the nature of these terrorists, it could pose a threat eventually to American interests as well," Obama said.
But he said any U.S. action must be accompanied by political steps in Iraq to bridge the sectarian divide.
"We can't do it for them," Obama said. "And in the absence of this type of political effort, short-term military action, including any assistance we might provide, won't succeed."
ISIS's gains in Iraq have prompted the Iraqis to seek U.S. help to quell the extremists, and triggered accusations from Speaker John Boehner that Obama was "taking a nap."
Obama said though events on the ground are unfolding quickly, a U.S. plan is "going to take several days" to formulate. And, he said, any action will be "targeted and precise." He added the U.S. will also pursue diplomacy to resolve the issue.
"This is a regional problem. And it's going to be a long-term problem," Obama said. "And what we're going to have to do is combine selective actions by our military to make sure we're going after terrorists who could harm our personnel overseas or, eventually, hit the homeland.
"We're going to have to combine that with what is a very challenging international effort."
In London today, Secretary of State John Kerry called for regional efforts to preserve stability in Iraq.
"Everybody in the region, every country that understands the importance of stability in the Middle East, needs to be concerned about what is happening with ISIL in Iraq today," Kerry said.
His comments were reported by The Associated Press.
The AP also reported that the Pentagon is examining a range of military options in Iraq. Here's more:
"One of the immediate moves could be to position small teams of military troops and aircraft close by in case they are needed to evacuate U.S. personnel or to provide security if required.
"More aggressive options include airstrikes and other counterterrorism operations against the insurgency, in conjunction with or with the approval of the Iraqi government. The U.S. routinely has an array of ships in the region.
"On Friday, the aircraft carrier USS George H.W. Bush and an accompanying Navy cruiser were in the northern Arabian Sea, while two Navy destroyers from the Bush strike group had already moved into the Persian Gulf.
"The ships carry Tomahawk missiles, which could reach Iraq, and the Bush is carrying fighter jets that could also easily get to Iraq."