TOPSHOT - Turkish-backed Syrian fighters take up an armed position with sandbags along the frontline with SDF forces near the village of Kiridiyah, about 30 kilometres west of the northern town of Manbij, on January 15, 2019.  / AFP / Bakr ALKASEM
Turkish-backed Syrian fighters take up an armed position with sandbags along the frontline with SDF forces. AFP 

SDF locked in pitched battles with 'diehard' ISIS fighters in east Syria