I believe the answer is:
- fighting among tribes
In newly independent nations, there tend to be a vacuum that attracted many groups in competition to obtain the largest power, which caused the fight among tribes
- unstable governments
since there isn't legitimate government that acknowledged by the people, they cannot make a uniftying political actions that sink the country into disarrat
- issues resulting from the Cold War
The western and eastern block often seek alliances from these nations to strengthen their position in the cold war.
