Zeinab Badawi speaks to Salih Muslim Mohammed, leader of Syrian Kurdish party the PYD, which is part of the National Coordination Body for Democratic Change, a secular, pro-democracy coalition inside Syria. The extremist group ISIS is expanding its foothold in Syria, after its recent gains in neighbouring Iraq. The first town it seized was Raqqa in northern Syria a year ago, it holds parts of Aleppo province in the north as well as more territory on the border with Iraq. ISIS is now engaging in battles with other rebel groups in Syria, splintering efforts by the opposition who now find themselves battling both ISIS forces and government troops. What does the advance of ISIS mean for moderate secular opposition groups inside Syria?