Description:Rebels fight back in northwest Syria as they launch a new military operation in Idlib province. Plumes of black smoke mark the horizon -- the aftermath of the governments air campaigns. Both sides are fighting for control of the strategic region, which borders Turkey. Rebels patrol the streets in tanks. They are throwing everything they have into the fight. 21 rebels were killed on Wednesday alone. The wounded are treated in makeshift hospitals. Supplies are short.(1:07)