But he said the broader effort was intended to help Iraqis meet the threat from the militants over the long term. “The most important time table that I’m focused on right now is the Iraqi government getting formed and finalized,” the president said before boarding Marine One.

Mr. Obama described for the first time a more complicated effort to rescue Iraqis stranded on Sinjar Mountain, saying that the American military and others might have to create a safe corridor down the mountain. “The next step, which is going to be complicated logistically, is how can we give people safe passage,” Mr. Obama said.

He suggested that helping those people make it to safety would take time. He also said that getting an inclusive Iraqi government formed, and giving all Iraqis a reason to believe that they are represented by that government, would help give Iraqi military forces a reason to fight back against the militants.