sentences:  On 22 July the Marines launched a three battalion operation against PAVN supply lines south of the Cua Viet River.The 5th Battalion would be landed by HMM-164 helicopters 4km north of the city, while the other two battalions, supported by tanks would attack north, the combined force would then move southeast.The helicopter landing proceeded smoothly, while the ground assault met heavy resistance and could only break through PAVN defenses with air and artillery support.