 Complete the following phrase:  The South African administration continued the so-called Police Zone in south, a region created by the Germans covering about two-thirds of the province later to become Namibia. Ovambo people were not allowed to move into the Police Zone, neither other tribes nor Europeans could move north without permits. This isolated the Ovambo people. However, because of labor shortage in the Police Zone and South Africa, in part because of massacre of native Africans such as through the 