"Our message to anyone who harms our people is simple: America does not forget, our reach is long, we are patient, justice will be done," Obama said in a speech before the American Legion's annual convention in North Carolina. "We have proved time and time again we will do what's necessary to ... go after those who harm Americans. And we'll continue to take direct action where needed."
Obama nevertheless reiterated his previous promise that the U.S. would not deploy any ground troops in its fight against jihadist Islamic State forces in the region.
"We have to use our power wisely. History teaches us of the danger of overreaching and spreading ourselves too thin," Obama said. "Let me say it again: American combat troops will not be returning to fight in Iraq. We will not allow the United States to be dragged back into another ground war in Iraq."
The U.S. launched airstrikes against Islamic State in Iraq earlier this month and may be considering similar action in Syria.