 Khe Sanh and its 6 @,@ 000 U.S. Marine Corps , Army , and ARVN defenders was surrounded by two to three North Vietnamese divisions , totaling approximately 20 @,@ 000 men . Throughout the siege , which lasted until 8 April , the allies were subjected to heavy mortar , rocket , and artillery bombardment , combined with sporadic small @-@ scale infantry attacks on outlying positions . With the exception of the overrunning of the U.S. Special Forces camp at Lang Vei , however , there was never a major ground assault on the base and the battle became largely a duel between American and North Vietnamese artillerists , combined with massive air strikes conducted by U.S. aircraft . By the end of the siege , U.S Air Force , Marine Corps , and Navy aircraft had dropped 39 @,@ 179 tons of ordnance in the defense of the base . 
