What was the name of the group that supplied money and materials to the rebel group fighting diem?

Viet Cong is the name of the group that supplied money and materials to fight Diem. It was a network of communist agent and subversives that supplied and controlled  North Vietnam under the leader, Le Duan. However, the movement did its underground operations in the South, Le Duan wanted the communist to rise up and overthrow the South Vietnam leader Diem who had foreign advisors who were against communism.