Human rights workers in South Sudan are reporting that ethnically-motivated violence is spiralling, and could amount to war crimes. Fighting, which broke out in the capital Juba, has now spread, splitting the country along ethnic lines. Government troops loyal to President Salva Kiir, an ethnic Dinka, are pitched against defectors, who are loosely grouped under the leadership of ethnic Nuer former vice-president Riek Machar. Thousands are already dead, and hundreds of thousands more displaced.