Are you asking if sub saharan groups or tribes ever had conflicts/wars among themselves? I am not familiar with the term interracism, can you describe what it means? Thanks

Sudan is constantly trying to exterminate it's Southern dark-skinned christian population. They differ from the North who are Muslim and Afro-Semitic. They differ in two ways, the South are (were) also largely excluded from government but there were oil reserves in the area so it was a conflict with many many motives.

The South seceded and promptly began killing each other on tribal lines. The darker tribes (races?) are Dinka and another one.

I think tribalism is what you mean to ask. Racism is a form of tribalism and yes, it is very rife in Africa. Since the first humans split perhaps. There is favouritism in business contracts, all types of jobs, marriage, every facet of life where it can fit in it does.

Kenya, where I live has more than 40 tribes and there is little love between them, especially among the old who knew dictators who'd made the country's armed forces almost exclusively consist of their own tribe and tilted the scales everywhere else heavily to that side to give them something to fight for. They are extremely suspicious and vote one way only, for the biggest name from their tribe.

A neighbouring country known as Tanzania has very little tribalism. Their leaders never deepened pre-existing divides to make it easier to rule. Most leople identify as Tanzanian instead of as Chegge, Nyamwezi or whatever. I have never heard a Tanzanian mention their tribe.

Most countries follow the Kenyan and Sudanese example. Murder is also very common between tribes in the more rural areas. When disputes occur in areas where people are armed between tribes, or even clans as in Somalia, war soon follows. Not necessarily armed with guns, machetes, spears, bows and arrows are also frequently used.