Much of Iraq is now in chaos, and fighters from the the Islamic State in Iraq and Syria (ISIS), are fueling the instability, attacking towns at will and making large gains in territory. Last week, ISIS militants swarmed into several minority villages in northern Iraq, prompting tens of thousands of Yazidis and Christians to flee for their lives during their push toward the Kurdish regional capital of Arbil. Iraq's human rights minister told Reuters that IS militants have killed at least 500 members of Iraq's Yazidi ethnic minority during their offensive. U.S. warplanes bombed ISIS fighters and weapons on Friday after President Barack Obama said Washington must act to prevent "genocide." At least 20,000 civilians who had been besieged by jihadists on Sinjar mountain have safely escaped to Syria and been escorted by Kurdish forces back into Iraq, officials said. Thousands more are still feared to be trapped in the region, forced to choose between starvation and dehydration, or a descent down the mountains toward armed militants.