Some 200 people gathered outside the British High Commission in Rwanda to protest at the arrest of intelligence chief Karenzi Karake in London.
Gen Karake, 54, was detained at Heathrow Airport on Saturday, accused of ordering massacres in the wake of the 1994 Rwanda genocide.
Protestors have threatened not to end the demonstration in the capital, Kigali, until the general is released.
The Rwandan government has branded the arrest an «outrage».
Louise Mushikiwabo, Rwanda’s Foreign Minister condemned Gen Karake’s detention on Tuesday, saying that «Western solidarity in demeaning Africans is unacceptable».
«We are here to stand in solidarity with our hero, who was among the people who stopped genocide in this country,» Herbert Muhire, a protest leader told The Associated Press news agency.
William Gelling, the UK’s High Commissioner to Rwanda, addressed the crowd briefly.
«All I can say is that this was a legal decision as you understand, on behalf of the Spanish legal authorities.
«The UK is a very close partner with Rwanda,» he said, as quoted by AP.