Battle of Ban Houei Sane The Battle of Ban Houei Sane was a battle of the Vietnam War that began on the night of 23 January 1968 , when the 24th Regiment of the North Vietnamese 304th Division overran the small Laotian Army outpost at Ban Houei Sane . The fighting at Ban Houei Sane was one in a series of battles fought between Communist and Allied forces during the Tet Offensive . The small outpost , defended by the personnel of the 33rd Elephant Battalion ( BV - 33 ) , was attacked and overwhelmed by the vastly superior North Vietnamese Army and their PT - 76 light tanks . The failure of the 33rd Elephant Battalion to defend their outpost at Ban Houei Sane would have negative consequences only a few weeks later , when the North Vietnamese would strike again at Lang Vei . Background . During the First Indochina War the Viet Minh constructed a pathway in neighbouring Laos in order to transport vital military supplies to southern Vietnam . Over time that pathway , now known as the Ho Chi Minh Trail , grew in importance as the government of the Democratic Republic of Vietnam sought to topple the rival government in the south , the Republic of Vietnam . In the late 1950s , the Ho Chi Minh Trail was expanded to support the Viet Cong ( VC ) ' s increasing military activities in southern Vietnam . To protect this vital lifeline , North Vietnamese forces were deployed to take control of various areas in eastern Laos adjacent to the Demilitarized Zone . The increasing Communist activities in those parts of Laos did not go unnoticed , as the governments of South Vietnam and Laos began working together to establish a small outpost at Ban Houei Sane for the purpose of monitoring Communist movements in 1959 . In April 1961 , the newly created 33rd Elephant Battalion ( BV - 33 ) of the Royal Laotian Army arrived at Ban Houei Sane , after it was forced to retreat from Tchephone by North Vietnamese and Pathet Lao forces . At Ban Houei Sane , the Laotians constructed new defensive positions with assistance from the Army of the Republic of Vietnam ' s 1st Infantry Division . One year later , BV - 33 began monitoring North Vietnamese movements along the Vietnam - Laotian border . Battle . By the mid - 1960s , when U . S military forces increased their presence in South Vietnam , the Laotian units at Ban Houei Sane also detected increasing North Vietnamese movements along the Ho Chi Minh Trail . And towards the end of December 1967 six thousand trucks carrying supplies for Communist forces in southern Vietnam were detected moving down the Trail . That tremendous build - up came as a result of North Vietnam ' s decision to launch an all - out attack on Allied forces during the Tet celebrations . In order to lure American combat units away from the major cities the North Vietnamese High Command decided to launch the first strike ; on 21 January 1968 , regular units of the North Vietnamese Army began their attacks on the Khe Sanh Combat Base , where six thousand U . S Marines were stationed . As part of that major effort , General Tran Quy Hai made the decision to knock out the small outpost of Ban Houei Sane once and for all , as the Royal Laotian Army ' s 33rd Elephant Battalion were considered an important tool in the Allies ' intelligence gathering effort . On the night of 23 January 1968 , the North Vietnamese 24th Regiment struck the defenders of Ban Houei Sane from three directions . Initially the North Vietnamese assault was spearheaded by the 3 / 24 Battalion with the 198th Armoured Battalion in support , but the first assault wave was delayed for various reasons . Firstly North Vietnamese infantry and armoured corps lacked the experience in combined operations , secondly the local terrain posed many difficulties for North Vietnamese tank crews , causing the PT - 76 light tanks to bog down attempting to cross a stream . By 06 : 00 Colonel Lê Công Phê ordered his troops to advance on Ban Houei Sane despite the delays of the 198th Armoured Battalion . As North Vietnamese units moved towards the Laotian outpost , the PT - 76 ' s of the 198th Battalion turned up causing much confusion . On the day the North Vietnamese launched their attacks , the weather was poor for aerial operations . As North Vietnamese engineers blew up Laotian obstacles there was little that U . S Forward Air Controllers could do to stop the North Vietnamese advance as ground targets could not be identified . After three hours of fighting the Laotian commander , Lieutenant Colonel Soulang Phetsampou , informed the U . S Forward Air Controllers that all Laotian positions had been overwhelmed and that they would abandon the outpost . At that point , the Laotian commander requested assistance from the CIDG camp at Lang Vei , to help evacuate his soldiers and their families . However assistance from Lang Vei would never arrive , so the soldiers of BV - 33 and more than two thousand civilian refugees made their way eastward along Route 9 , approaching the South Vietnamese border . On 24 January , the survivors of the Ban Houei Sane battle and their families had crossed the South Vietnamese border , reaching the Lang Vei CIDG camp . Initially the military personnel at Lang Vei treated the Laotian refugees with caution , but they were finally given assistance when the Lang Vei camp commander allowed the Laotians to take up positions in the nearby Lang Vei village . The next target . For Captain Frank C . Willoughby , commander of the Lang Vei CIDG camp , the arrival of the Laotian refugees also brought some disturbing development on the battlefield . For the first time the North Vietnamese deployed tanks in battle , and it was only fifteen kilometres away from Lang Vei . Fearing a repeat of the deadly North Vietnamese attacks , BV - 33 soldiers were allowed to assist local forces by conducting patrols around the CIDG camp . As the Laotians settled down in Lang Vei , the U . S Air Force conducted airstrikes targeting the Ban Houei Sane airfield to prevent the North Vietnamese from utilising the airfield for operations against Khe Sanh . On 30 January , Captain Willoughby ' s fears were confirmed when a North Vietnamese soldier defected to the special forces at Lang Vei , and informed them of the whereabouts of the North Vietnamese 304th Division . On 6 February 1968 , the North Vietnamese struck Lang Vei .