A deserted stronghold that belonged to Islamic State fighters is seen in Tel Abyad town, Raqqa governorate, June 16, 2015. With a string of victories over Islamic State, Syria's Kurds are proving themselves an ever more dependable ally in the U.S.-led fight against the jihadists and building influence that will make them a force in Middle Eastern politics. Aided by U.S.-led air strikes, the Kurdish-led YPG militia may have dealt Islamic State its worst defeat to date in Syria by seizing the town of Tel Abyad at the Turkish border, cutting a supply route to the jihadists' de facto capital of Raqqa city. The text on the wall reads: "Islamic Caliphate State, accountability center, the succession to the Platform of prophecy." REUTERS/Rodi Said