Kurdish fighters took full control of the border town of Tal Abyad on Tuesday, dealing a major blow to the Islamic State group’s ability to wage war in Syria by cutting off a vital supply line to its self-proclaimed capital of Raqqa. A senior Kurdish commander, Haqi Kobane, told The Associated Press that Kurdish units known as the YPG that he leads, along with their allies from the Free Syrian Army, were starting to clear booby traps and mines in the town along the border with Turkey. The extremists had been in control of it for more than a year. “Daesh has been broken at the hands of the YPG. … It is a victory for all Syrians,” he said by telephone from northern Syria, using the Arabic acronym for the Islamic State group.