A black flag belonging to the so-called Islamic State is seen in the Syrian town of Kobani on Thursday, as seen from the Turkey-Syria border near the southeastern town of Suruc. Umit Bektas/Reuters/Landov hide caption

itoggle caption Umit Bektas/Reuters/Landov

Leon Panetta says he and other top national security advisers to the president argued to keep some U.S. forces on the ground in Iraq after 2011. Frederic J. Brown/AFP/Getty Images hide caption

itoggle caption Frederic J. Brown/AFP/Getty Images

Smoke rises from the Syrian town of Kobani, seen from near the Mursitpinar border crossing on the Turkish-Syrian border in the southeastern town of Suruc, Sanliurfa province, on Friday. Murad Sezer/Reuters/Landov hide caption

itoggle caption Murad Sezer/Reuters/Landov

Displaced demonstrators from the minority Yazidi sect demonstrate outside the United Nations offices in Irbil, Iraq, on Aug. 4 in support of those held captive by the self-proclaimed Islamic State. Azad Lashkari/Reuters/Landov hide caption

itoggle caption Azad Lashkari/Reuters/Landov

Islamic State flags on the Mullah Abdullah bridge in southern Kirkuk earlier this week. A U.N. report says the extremist group has perpetrated possible war crimes and crimes against humanity. Reuters/Landov hide caption

itoggle caption Reuters/Landov