 During the first days of the North Vietnamese occupation , U.S. intelligence vastly underestimated the number of PAVN troops and little appreciated the effort that was going to be necessary to evict them . General Westmoreland informed the Joint Chiefs that " the enemy has approximately three companies in the Huế Citadel and the marines have sent a battalion into the area to clear them out . " Since there were no U.S. formations stationed in Huế , relief forces had to move up from Phu Bai , eight kilometers to the southeast . In a misty drizzle , U.S. Marines of the 1st Marine Division and soldiers of the 1st ARVN Division and Marine Corps cleared the city street by street and house by house , a deadly and destructive form of urban combat that the U.S. military had not engaged in since the Battle of Seoul during the Korean War , and for which neither side were trained . Because of the historical and cultural significance of the city , American forces did not immediately apply air and artillery strikes as widely as they had in other cities . 
