20-21 Estimated NVA battalion attacks K/3/26 on Hill 861. Jan After penetrating southwestern portion of Marines' perimeter, the enemy is repulsed leaving 47 dead; NVA reserves are hit by heavy air strikes and artillery fire. 21 Jan KSCB comes under heavy mortar, artillery, and rocket attack which destroys main ammunition dump. NVA battalion attacks and partially overruns Khe Sanh village before CAC and RF companies drive off enemy. After second attack, Col Lownds withdraws defenders to confines of combat base. 22 Jan ComUSMACV initiates Operation NIAGARA to provide massive air support for Khe Sanh. LtCol Mitchell's 1/9 arrives KSCB and takes up positions which encompass rock quarry southwest of combat base. E/2/26 is relocated from Hill 558 to prominent ridgeline northeast of 861 as covering force for flank of 2/26; E/2/26 passes to operational control of 3d Battalion. New position is called 861A. 23-28 Large number of tribesmen and families are evacuated Jan from Khe Sanh area to avoid hostile fire. 27 Jan 37th ARVN Ranger Battalion arrives KSCB and takes up positions in eastern sector of combat base. 30 Jan Communists launch nation-wide TET Offensive. 5 Feb NVA battalion attacks E/2/26 on Hill 861A in concert with heavy shelling of KSCB. Enemy gains foothold in northern sector of Company E perimeter but is driven out by savage counterattack; 109 NVA and 7 Marines KIA. 7 Feb Special Forces camp at Lang Vei overrun by enemy battalion supported by PT-76 Soviet-built tanks; first use of NVA tanks in South Vietnam. 8 Feb Some 3,000 indigenous personnel, both military and civilian, from Lang Vei move overland to Khe Sanh. After being searched and processed, several hundred refugees are air evacuated. 8 Feb A/1/9 combat outpost 500 meters west of 1/9 perimeter hit and partially overrun by reinforced NVA battalion. During three-hour battle, reinforcements drive NVA from Marine position and with aid of supporting arms kill 150 North Vietnamese; Col Lownds decides to abandon outpost and units withdraw to 1/9 perimeter. 10 Feb Marine C-130 of VMGR-152, hit by enemy fire during approach, crashes after landing at Khe Sanh and six are killed. Feb-Apr Paradrops, low-altitude extraction systems, and helicopters are primary means of resupplying 26th Marines due to bad weather and heavy enemy fire.