Syrian Violence Escalates

against a fierce assault with government firepower. Alex marquardt has made his way to northern syria and the mother of all battles. Alex? Reporter: Good evening. Fighting continues to rage today in... See More

against a fierce assault with government firepower. Alex marquardt has made his way to northern syria and the mother of all battles. Alex? Reporter: Good evening. Fighting continues to rage today in aleppo, syria's commercial capital. Regime forces shelled neighborhoods recently taken by opposition forces who are desperately clinging on and calling for heavier weapons. We crossed into syria early this morning. Our first stop was ater ebd that has seen heavy violence. The devastation was stagger. Hardly a single building left untouched and virtually a ghost town. Also remarkable was traveling all day across northern syria, we didn't see a single government tank or troop, which tells you how far these opposition forces have come but until they take a city like aleppo they still have a long