“All human beings are God’s children”
The Ponovizer Rov, Rav Kahanaman zt’l used to visit South Africa a lot as he had relatives there and the Jewish community there has mainly Lithuanian roots.
He once visited the Chofetz Chaim zt’l after one of these visits, and the Chofetz Chaim asked him about how the black people in south Africa were doing and that he had heard they were being persecuted.
Rav Kahanaman asked the Chofetz Chaim what his interest was in south african affairs.
The Chofetz Chaim replied that they are also G-d’s people and he needs to be concerned about their welfare.
(heard from Rabbi Abraham Tanzer שליטא , Rosh Yeshiva of Yeshiva College of South Africa)
yoniisaacson.com 
Interesting story, but did it really happen as stated?
The Chofetz Chaim passed away in 1933. That was long before the apartheid of the National Party, Verwoerd, etc., was put into place. Was South Africa then really different from other countries in Africa under colonial rule (many others were at the time)?
If such a story occurred, perhaps it was about Africa in general, not specifically SA?
On another note, can it be researched re when R. Kahaneman visited SA, and if he did so before the end of 1933? I suspect that most of his visits (if not all of them) were made in later years, such as after WWII, when advances in transportation made them much quicker and easier, and when he was rebuilding his Yeshiva in Eretz Yisroel.