Meanwhile, in Syria, the U.S.-backed, Kurdish-led troops known as the Syrian Democratic Forces launched a campaign Sunday to take control of the city of Raqqa from ISIS. The U.S., France and Britain have all pledged to back the campaign with airstrikes. U.S. Central Command says the U.S.-led coalition has already conducted 16 airstrikes north of Raqqa since Sunday. An estimated 200,000 people currently live in Raqqa, which was seized by ISIS militants in 2014.