African people incarcerated when borders removed (4)

I believe the answer is:

hutu

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'african' is the definition.
(Hutus are an African ethnic group)

I don't understand the rest of the clue.

(Other definitions for hutu that I've seen before include "A member of one Rwandan people" , "Bantu speaker from Rwanda or Burundi" , "African" , "Rwandan or Burundian" , "Africans" .)

I've seen this clue in The Guardian.

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