active along the Benguela railway, repeatedly causing damage to the Portuguese, and to the Republic of Congo and Zambia, both of which used the railway for transportation of their exports to Angolan ports. On 19 May 1968, FNLA entered Eastern Angola and carried out its first violent actions in the region against the local populations. During October 1968, the Portuguese forces initiated Operation (Victory) against the MPLA, assaulting and destroying its main bases at Eastern Angola. Among others, the Mandume III base (headquarters of the MPLA's III Military Region) was assaulted by the Portuguese Commandos, leading to the capture of important documents. During the late 1960s, the FNLA and MPLA fought each other as much as they did the Portuguese, with MPLA forces assisting the Portuguese in finding FNLA hideouts. In the late 1969, the Portuguese forces organize the Battle Group Sirocco ( Siroco), a highly mobile composite task force aimed at hunting and destroying the guerrilla forces operating in Eastern Angola. The land component of the task force was centered in Commando companies, being supported by an air component with helicopters and light aircraft. On 1 September, Battle Group Sirocco initiated a long series of highly successful operations in the Eastern region. Battle Group Sirocco (remodeled as Sirocco 1970 and Sirocco 1971, respectively in 1970 and 1971) would be active for three years, in 1972 being replaced by the similar Battle Group Ray ( Raio). Portuguese re-focus to the East The MPLA began forming squadrons of 100 to 145 militants in 1971. These squadrons, armed with 60 mm and 81 mm mortars, attacked Portuguese outposts. The Portuguese conducted counter-insurgency sweeps against MPLA forces in 1972, destroying some MPLA camps. Additionally, the South African Defence Force engaged the MPLA forces in Moxico in February 1972, destroying the Communist presence. The Portuguese Armed Forces organised a successful campaign to control and pacify the entire Eastern Front (the Frente Leste). Neto, defeated, retreated with 800 militants to the Republic of the Congo. Differing factions in the MPLA then jockeyed for power until the Soviet Union allied with the Chipenda faction. On 17 March 1,000 FNLA fighters mutinied in Kinkuzu, but the Zairian army put down the rebellion on behalf of Roberto. In 1973 Chipenda left the MPLA, founding the Eastern Revolt with 1,500 former MPLA followers. Tanzanian President Julius Nyerere convinced the People's Republic of China, which had begun funding the MPLA