Portuguese documents reveal that over the course of the liberation war, nearly two-thirds of all military engagements against the Portuguese involved the MPLA and over a third the FNLA, while less than 5% involved UNITA.  Outside of the country UNITA received support from the United States and South Africa. The infighting between and within the three nationalist movements reduced their effectiveness against the Portuguese, and by 1974 little progress had been made to overthrow the colonial government.