Ladislas Ntaganzwa, 53, one of the last suspects wanted for taking part in the 1994 Rwandan genocide has been arrested in neighbouring Democratic Republic of Congo.
The UN says Ntaganzwa is accused of organising mass rapes and the massacre of thousands.
Ntaganzwa and his lawyers have not commented on the allegations.
Earlier on, the US has issued a $5m (£3.2m) reward for his arrest, calling him “one of the main instigators of the genocide”.
The fugitive was one of nine suspects still wanted by the UN for their alleged role in the genocide, which left about 800,000 people dead. The others are still at large.
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