Three North Vietnamese divisions attack An Loc with infantry, tanks, heavy artillery and rockets, taking half the city after a day of close combat. An Loc, the capital of Binh Long Province, was located 65 miles northwest of Saigon.

This attack was the southernmost thrust of the three-pronged Nguyen Hue Offensive (later more commonly known as the “Easter Offensive”), a massive invasion by North Vietnamese forces designed to strike the knockout blow that would win the war for the communists. The attacking force included 14 infantry divisions and 26 separate regiments, with more than 120,000 troops and approximately 1,200 tanks and other armored vehicles. The main North Vietnamese objectives, in addition to An Loc in the south, were Quang Tri in the north, and Kontum in the Central Highlands. Initially, the South Vietnamese defenders in each case were almost overwhelmed, particularly in the northernmost provinces, where the South Vietnamese abandoned their positions in Quang Tri and fled south in the face of the enemy onslaught.

In Binh Long, the North Vietnamese forces crossed into South Vietnam from Cambodia to strike first at Loc Ninh on April 5, then quickly encircled An Loc, holding it under siege for almost three months while they made repeated attempts to take the city. The defenders suffered heavy casualties, including 2,300 dead or missing, but with the aid of U.S. advisors and American airpower, they managed to hold An Loc against vastly superior odds until the siege was lifted on June 18. Fighting continued all over South Vietnam throughout the summer months, but eventually the South Vietnamese forces prevailed against the invaders, even retaking Quang Tri in September. With the communist invasion blunted, President Nixon declared that the South Vietnamese victory proved the viability of his Vietnamization program, instituted in 1969 to increase the combat capability of the South Vietnamese armed forces.