The rebels who had coordinated the 1961 uprisings later began to undertake effective military organization. The several nationalist organizations set up training camps and attracted external military aid. In the summer of 1961, for example, the UPA, which had strong support among the Bakongo, formed the National Liberation Army of Angola (Exército de Libertação Nacional de Angola -- ELNA), a force of about 5,000 untrained and poorly armed troops. Subsequently, groups of Angolans went to Morocco and Tunisia to train with Algerian forces, then fighting for their own nation's independence. After winning its independence in 1962, Algeria supplied the ELNA with arms and ammunition.

In March 1962, the UPA joined with another small Kongo nationalist group, the Democratic Party of Angola (Partido Democrático de Angola -- PDA) to form the FNLA. The FNLA immediately proclaimed the Revolutionary Government of Angola in Exile (Govêrno Revolucionário de Angola no Exílo--GRAE). The president of the FNLA/GRAE, Holden Roberto, declared his organization to be the sole authority in charge of anti-Portuguese military operations inside Angola. Consequently, he repeatedly refused to merge his organization with any other budding nationalist movement, preferring to build the FNLA/GRAE into an all-Angolan mass movement over which he would preside.

By 1963, with training and arms from Algeria, bases in Zaire, and funds from the Organization of African Unity (OAU), the FNLA/GRAE military and political organization was becoming formidable. Still, it made no significant territorial gains.

Meanwhile, the MPLA, which had been behind the initial uprisings in Luanda in February 1961, had suffered a great deal from Portuguese reprisals, with many of its militant leaders dead or in prison. The rebuilding of the MPLA was substantially aided in 1962 by the arrival of Agostinho Neto, an assimilated Mbundu physician who had spent several years in jail for expressing his political views and had recently escaped from detention in Portugal. Neto attempted to bring together the MPLA and Roberto's FNLA/GRAE, but his efforts were thwarted by Roberto's insistence that his organization represented all Angolans.

Initially based in Kinshasa, as was the FNLA/GRAE, in 1963 the MPLA shifted its headquarters to Brazzaville (in present-day Congo) because of Roberto's close ties to Zairian president Mobutu Sese Seko. From Brazzaville, the MPLA launched small guerrilla operations in Cabinda, but the movement was militarily far weaker than the FNLA. Moreover, it lacked an operations base from which it could reach the densely populated north and center of Angola.

As it dragged on into 1964 and 1965, the conflict became stalemated. Hampered by insufficient financial assistance, the insurgents were unable to maintain offensive operations against a fully equipped Portuguese military force that had increased to a strength of more than 40,000. The FNLA settled into a mountain stronghold straddling the border of Uíge and Zaire provinces and continued to carry on guerrilla activities. The insurgents found it increasingly difficult to sustain the cohesion they had achieved after 1961 and 1962. Between 1963 and 1965, differences in leadership, programs, and following between the FNLA and the MPLA led to open hostilities that seriously weakened each group's strength and effectiveness.

Data as of February 1989