In 1941 at the beginning of the war, blacks numbered nearly 150,000 in Detroit, which had a total population of 1,623,452. Many of the blacks had migrated from the South in 1915 to 1930 during the Great Migration, as the auto industry opened up many new jobs. By summer 1943, after the United States had entered World War II, tensions between whites and blacks in Detroit were escalating; blacks resisted discrimination, as well as oppression and violence by the Detroit Police Department. The police force of the city was overwhelmingly white and the black population resented this.