Kongo. Though as foreigners skilled Angolans could not take advantage of Mobutu Sese Seko's state employment programme, some found work as middlemen for the absentee owners of various lucrative private ventures. The migrants eventually formed the FNLA with the intention of making a bid for political power upon their envisaged return to Angola. A largely Ovimbundu guerrilla initiative against the Portuguese in central Angola from 1966 was spearheaded by Jonas Savimbi and the National Union for the Total Independence of Angola (UNITA). It remained handicapped by its geographic remoteness from friendly borders, the ethnic fragmentation of the Ovimbundu, and the isolation of peasants on European plantations where they had little opportunity to mobilise. During the late 1950s, the rise of the Marxist–Leninist Popular Movement for the Liberation of Angola (MPLA) in the east and Dembos hills north of Luanda came to hold special significance. Formed as a coalition resistance movement by the Angolan Communist Party, the organisation's leadership remained predominantly Ambundu and courted public sector workers in Luanda. Although both the MPLA and its rivals accepted material assistance from the Soviet Union or the People's Republic of China, the former harboured strong anti-imperialist views and was openly critical of the United States and its support for Portugal. This allowed it to win important ground on the diplomatic front, soliciting support from nonaligned governments in Morocco, Ghana, Guinea, Mali, and the United Arab Republic. The MPLA attempted to move its headquarters from Conakry to Léopoldville in October 1961, renewing efforts to create a common front with the FNLA, then known as the Union of Angolan Peoples (UPA) and its leader Holden Roberto. Roberto turned down the offer. When the MPLA first attempted to insert its own insurgents into Angola, the cadres were ambushed and annihilated by UPA partisans on Roberto's orders—setting a precedent for the bitter factional strife which would later ignite the Angolan Civil War. Angolan Civil War Throughout the war of independence, the three rival nationalist movements were severely hampered by political and military factionalism, as well as their inability to unite guerrilla efforts against the Portuguese. Between 1961 and 1975 the MPLA, UNITA, and the FNLA competed for influence in the Angolan population and the international community. The Soviet Union and Cuba became especially sympathetic towards the MPLA and supplied that party with arms, ammunition, funding, and training. They also backed UNITA militants until it became clear that