Two months later, the Nama people broke out in a similar rebellion against German colonists. Traditional rivalries prevented the Herero and Nama from joining together, however both groups continued fighting guerrilla warfare against the German colonial forces. Following the abandonment of Lothar von Trotha's policy of exterminating Herero within the borders of German South West Africa by denying them access to water holes, the colonial authorities adopted a policy of sweeping the bush clear of Herero – both civilians and rebels – and removing them, either voluntarily or by force, to concentration camps.