In a new twist in Turkey’s mounting offensive against Kurdish forces in northeastern Syria, Islamic State has claimed responsibility for a fatal car bomb attack. According to the Kurdish-led Syrian Democratic Forces (SDF), the attack took place on Friday in a market area of the mostly Kurdish town of Qamishli, killing four people and wounding nine. The area was under Turkish shelling at the time. The Reuters news agency said that several ISIS personnel had escaped from a jail there during the mayhem. The SDF, led by its Kurdish YPG militia, had been instrumental in stripping ISIS of its populated strongholds in Syria during an internationally backed offensive at the beginning of the year. Many YPG fighters were killed in the effort, and its forces took over responsibility for imprisoning ISIS fighters who had been captured, and holding members of their families in detention camps. Reuters reported that women being held in the Qamishli camp set fire to several tents and assaulted Kurdish guards with rocks and sticks. A major concern surrounding the Turkish offensive is that ISIS personnel will exploit the fighting to escape captivity and regroup, creating another front for violence and instability.