The method chosen by PAVN (People's Army of Viet Nam - North Vietnamese Army) to defeat the invasion was to first isolate the northern firebases by utilizing anti-aircraft artillery. The outposts would then be pounded by round-the-clock mortar, artillery, and rocket fire. Although the ARVN firebases were themselves equipped with artillery, their guns were quickly outranged by PAVN's Soviet-supplied 122mm and 130mm pieces, which simply stood off and pounded the positions at will. The defensive edge that could have been provided by the utilization of tactical B-52 bomber strikes was nullified by the close-in tactics of the communist forces. Massed ground attacks, supported by artillery and armor would then finish the job. As early as 18 February North Vietnamese forces had begun attacks by fire on Rangers North and South. On the following day the attacks shifted to Ranger North. Ground operations against the outpost were conducted by the 102nd PAVN Regiment of the 308th Division supported by Soviet-built PT-76 and T-54 tanks. The Rangers held on tenaciously throughout the night. President Thieu, oblivious to the previous nights attacks, and who was visiting I Corps headquarters at the time, advised General Lam to postpone the advance on Tchepone and to shift the focus of the operation toward the southwest. By the afternoon of the 20th, the 39th ARVN Ranger Battalion had been reduced from 500 to 323 men and its commander ordered a retreat toward Ranger South, six kilometers away. Only 109 survivors reached Ranger South by nightfall. Although more than 600 North Vietnamese troops were estimated as killed during the action, casualties in the three-day fight totaled 75 percent of the ARVN battalion.
