u.s.-led coalition air support are battling to retake the key city of sinjar. that's a city where residents have fled from isis. cnn capturing that moment in 2014 in august. dozens of civilians desperately scrambling onto a military chopper in order to escape the terror group. right now officials say peshmerga troops have managed to secure a number of villages in that area. they've also taken control of an important stretch of highway used as an isis supply route into syria. cnn nick paton walsh is on the front lines outside of sinjar. he has more. >> reporter: just behind me, you can see the thick, black smoke that has been covering the center of sinjar since about this morning when the offensive began at first light. in the distance there's been pretty consistent exchanges of heavy machine gunfire. we're on the outskirts of sinjar because of the rules we agreed to when working with peshmerga in this imbed.