With the migration of African Americans Northward and the mixing of White and Black workers in factories, the tension was building, largely driven by White workers. The AFL, the American Federation of Labor, advocated the separation between White and African Americans in the workplace. There were non-violent protests such as walk-outs in protest of having African Americans and White working together. As tension was building due to advocating for segregation in the workplace, violence soon erupted. The East St Louis Illinois Riot, known for one of the bloodiest workplace riots, had between 40-200 killed and over 6000 African Americans displaced from their home. The NAACP, National Association for the Advancement of Colored People, responded to the violence with a march known as the Silent March. Over 10,000 African American men and women have demonstrated in Harlem, New York. Conflicts continue post World War 1, as African Americans continue to face conflicts and tension while the African American labor activism continues.