U.S. intelligence reports that an estimated 1,000 North Vietnamese troops have reoccupied Ap Bia Mountain (Hill 937), one mile east of the Laotian border. U.S. and South Vietnamese forces had fought a fierce battle with North Vietnamese troops there in May. The battle was part of a 2,800-man Allied sweep of the A Shau Valley called Operation Apache Snow. The purpose of the operation was to cut off the North Vietnamese and stop any infiltration from Laos that was menacing Hue to the northeast and Da Nang to the southeast. Paratroopers from the 101st Airborne had engaged a North Vietnamese regiment on the slopes of Hill 937, known to the Vietnamese as Ap Bia Mountain. Entrenched in prepared fighting positions, the North Vietnamese 29th Regiment repulsed the initial American assault and beat back another attempt by the 3rd Battalion, 187th Infantry on May 14. An intense battle raged for 10 days as the mountain came under heavy Allied air strikes, artillery barrages, and 10 infantry assaults.
On May 20, Maj. Gen. Melvin Zais, commanding general of the 101st, sent in two additional U.S. airborne battalions and a South Vietnamese battalion as reinforcements. The communist stronghold was finally captured in the 11th attack when the American and South Vietnamese soldiers fought their way to the summit of the mountain. In the face of the four-battalion attack, the North Vietnamese retreated to sanctuary areas in Laos.
During the intense fighting, 597 North Vietnamese were reported killed and U.S. casualties were 56 killed and 420 wounded. Due to the bitter fighting and the high loss of life, the battle for Ap Bia Mountain received widespread unfavorable publicity in the United States and was dubbed "Hamburger Hill" in the U.S. media (a name evidently derived from the fact that the battle turned into a "meat grinder"). Since the operation was not intended to hold territory but rather to keep the North Vietnamese Army off balance, the mountain was abandoned soon after the battle. The news of the battle and subsequent U.S. withdrawal from the area resulted in public outrage over what appeared to be a senseless loss of American lives. This furor only increased when it was revealed that the North Vietnamese had reoccupied their original positions after the American soldiers left. Gen. Creighton Abrams, who had succeeded Gen. William Westmoreland as commander of U.S. Military Assistance Command Vietnam, was ordered to avoid such battles in the future.