Fighters belonging to the Kurdish minority in Syria are increasingly becoming caught up in the conflict. One group, The Kurdish Popular Protection Force, is battling the Free Syrian Army (FSA) in the town of Ras al-Ain in the north. The FSA is accusing the Kurds of being Assad's mercenaries. But the Kurds say they are only protecting their own people. Al Jazeera's Sue Turton reports from the border between Turkey and Syria.