Part of a relief column composed mainly of South Vietnamese 21st Division troops finally arrives in the outskirts of An Loc. The division had been trying to reach the besieged city since April 9, when it had been moved from its normal station in the Mekong Delta and ordered to attack up Highway 13 from Lai Khe to open the route to An Loc. The South Vietnamese forces had been locked in a desperate battle with a North Vietnamese division that had been blocking the highway since the very beginning of the siege. As the 21st Division tried to open the road, the defenders inside An Loc fought off repeated attacks by two North Vietnamese divisions that had surrounded the city early in April. This was the southernmost thrust of the North Vietnamese invasion that had begun on March 30; the other main objectives were Quang Tri in the north and Kontum in the Central Highlands.
Although the lead elements of the 21st Division reached the outskirts of the city on this day, they did not represent significant reinforcements for An Loc, having suffered tremendous casualties in their fight up the highway and the two-month siege was not lifted. It would not be lifted until large numbers of fresh reinforcements were flown in to a position south of the city from which they then successfully attacked the North Vietnamese forces that surrounded the city. By the end of the month, most of the communist troops within the city had been eliminated, but the North Vietnamese forces still blocked Route 13 and continued to shell An Loc.
Also on this day: John Paul Vann, the senior U.S. advisor in the Central Highlands, is killed in a helicopter crash, probably shot down by a North Vietnamese unit. Vann had successfully directed the battle against the North Vietnamese invaders at Kontum.