The Kurds are involved in the Syrian crisis because of the whereabouts of their homes. In 2013, the Islamic State launched repeated attacks on Kurdish land in northern Syria, causing Kurds to get drawn in to the intense fighting there. During a battle close to the Turkish border, Turkish forces refused help, although it would have been easy to let Turkish Kurds battling ISIS into the country . Kurds have been fighting alongside the U.S. under the flag of the Syrian Democratic Forces since. Although the U.S. is allied with Kurdistan on the battlefield, they do not support Kurdish pleas for independence. The U.S. installed a no-fly zone in the 1990's to protect Kurds in the area of Iraq where they are situated. Since the monumental referendum the Kurds have had, Iraq has halted all flights from international airports to the Kurdish region.