 Nevertheless, the PAVN units stationed within the citadel were well dug in, had the advantage of terrain and mass artillery supports.An early ARVN victory was denied, and the fighting continue unabated.On 11 July, following preparatory B-52 strikes, the Vietnamese 1st Marine Battalion was deployed by HMM-164 and HMM-165 helicopters to two landing zones 2km northeast of the city to cut Route 560, the main PAVN supply line.