As the Viet Cong guerrillas were recruited from and lived among the local populace, outsiders found it virtually impossible to identify them. Their familiarity with the local terrain, their methods of operating in small groups, and massing for attacks mostly at night made locating them equally difficult. Even their patience seemed to enhance their ability to survive. Unwilling to engage a stronger military force and realizing that a specific government operation could not continue indefinitely, the Viet Cong normally would melt into their environment with the arrival of regular units. When the operation terminated and the regular government forces withdrew, the Communists would re-emerge, often stronger than before. In many cases the guerrillas could give real meaning to their anti-government propaganda once the local population had felt the weight of military operations in their particular community. Operating in this manner, the Viet Cong were able to husband their strength while simultaneously expanding their influence. There was ample indication that the Communist movement was not wholly indigenous to South Vietnam. Indeed, evidence of increasing North Vietnamese support for the Viet Cong was becoming apparent near the end of the decade. In May 1959, the Central Committee of the North Vietnamese Communist Party publicly announced its intention “to smash” the government of Ngo Dinh Diem.[3-4] By the summer of that year the Viet Cong were being reinforced with men and limited quantities of equipment infiltrated from North Vietnam. Many of the Communist infiltrators, who at this early stage were entering Diem’s country across the DMZ and by sea, were southerners who had gone North with the Viet Minh in late 1954. Trained in political and military operations, these returnees added substantially to the Viet Cong’s discipline and technical capabilities.[3-B] [3-B] A State Department publication released in 1965 placed the number of confirmed North Vietnamese infiltrators for the years 1959 and 1960 at 1,800. It also noted that an additional 2,700 North Vietnamese were estimated to have been infiltrated during this two-year period. The vast majority of these were thought to have been former residents of southern Vietnam. (Department of State, _Aggression from the North_, p. 33.)