President Obama on Friday said he is "very concerned" about Syria becoming a safe haven for terrorism if the Assad regime falls. "Because extremists thrive in chaos," Obama said at a press conference in Amman, Jordan with King Abdullah II. "They thrive in failed states, they thrive in power vacuums. They don't have much to offer when it comes to actually building things. But they're very good about exploiting the situations that are no longer function. They fill that gap."