By the end of 1949, the situation had radically changed with the success of the Chinese Communist People's Liberation Army (PLA) against the Nationalist Chinese. The PLA controlled the border with Vietnam, contact was made with the Viet Minh and the way was open for large scale support. In 1950, the war moved from the passive to the active stage. French troops were concentrated in fortresses in North Vietnam fighting a static war. During this year the Viet Minh swept along the frontier road with China, capturing fort after fort over a distance of 100 miles within 6 weeks. Then came Vinh Yen, a "set-piece" battle fought along conventional lines that resulted in a decisive French victory. This forced the Viet Minh to revert to a passive stage of revolutionary warfare and gave the French a false sense of security that the Viet Minh could never match them in a "set-piece" battle. The Viet Minh started rebuilding their forces in the Red River Delta and gaining control over, and support from, the villages. They again took the initiative, consistently interdicting French use of the roads. In the South, "Cochin China", the communist-led forces were too weak, lacking in arms and effective leadership, to prevail against the French. Moreover, the myriad sectarian interests present in the South, the Catholic areas and the domains of the Cao Dai, Hoa Hao and the Binh Xuyen, were satisfied to negotiate with the French for regional autonomy and prevented the formation of a broadly based popular front. Cao Dai and Hoa Hao were indigenous, syncretic religious sects created in the 20th century. The Binh Xuyen on the other hand was a drug and crime cartel operating in the Saigon-Cholon area. After being deprived of their private armies and regional autonomy by Diem, Cao Dai and to a lesser extent Hoa Hao continued to exist as religions. The Binh Xuyen on the other hand, took up banditry in the Rung Sat until they were finally suppressed or absorbed by the Viet Cong.