The Battle of Ia Drang was the first major battle between the United States Army and the People's Army of Vietnam (PAVN), also referred to as the North Vietnamese Army (NVA), and was part of the Pleiku Campaign conducted early in the Vietnam War. It comprised two main engagements, centered on two previously scouted helicopter landing zones (LZs), known as LZ X-Ray and LZ Albany. The first involved the 1st Battalion, 7th Cavalry Regiment and supporting units under the command of Lieutenant Colonel Hal Moore, and took place November 14-16, 1965 at LZ X-Ray, located at the eastern foot of the Chu Pong Massif in the central highlands of Vietnam. The second engagement involved the 2nd Battalion, 7th Cavalry Regiment plus supporting units under the command of Lieutenant Colonel Robert McDade, and took place on November 17 at LZ Albany, farther north in the Ia Drang Valley. It is notable for being the first large scale helicopter air assault and also the first use of Boeing B-52 Stratofortress strategic bombers in a tactical support role. Surrounded and under heavy fire from a numerically superior force, the American forces at LZ X-ray were able to hold off and drive back the North Vietnamese forces over three days of battle, largely through the support of both air power and heavy artillery bombardment, which the North Vietnamese lacked. LZ X-Ray was considered an American tactical victory, as the Americans claimed an almost 10:1 kill ratio. At LZ Albany, however, an American battalion was ambushed in close quarters. They were unable to use air and artillery support due to the close engagement of the North Vietnamese, and the Americans suffered an over-50% casualty rate before being extricated from the battle. Both sides, therefore, were able to claim victory in the battle.