The threat of infiltration across the demilitarized zone (DMZ) by the NVA was a main reason for strengthing northern I corps. Despite this move to counteract the enemy build-up in the area, movement of new NVA troops into South Vietnam continued. As a result, Operation Hastings, a coordinated Marine/South Vietnamese Army(ARVN) search and destrou mission, was launched on 7 July. Intelligence reports indicated that a veteran division of the NVA had moved into Quang Tri Province. Allied forces including 2/4 and 3/4 were deployted to the area and when contact was made the subsequent battle proved to be the most ferocious of the war up to that date. A feature of the battle was the number of sharp, small unit engagements that occurred. In one such encounter, an estimated enemy force of 1,000 hit two platoons of Company K, 3/4 on 18 July. Although the close-in fighting caused heavy casualties among enemy troops, the 3d Battalion's forces were only able to withdraw after artillery and air strikes were called in to support the beleaguered Leathernecks. The Communist attact cost the Americans over 60 casualties. Two members of the battalion--Captain Robert J. Modrezejewdki and Staff Sergeant John J. McGinty, III--were later awarded the Medal of Honor for their heroic action during this battle.