Tanzania and Zambia also served as transit points for incoming Soviet arms shipments. Though a relatively unified group during most of the civil war, divisions within the MPLA threatened its existence in its early years and into the 1970s.  At the root of the inner factionalism was the disparate backgrounds of MPLA members, which included both educated mesticos and assimilados as well as uneducated peasants.  Various groups formed factions that struggled for dominance within the movement.