In late January and primarily in early February 1941, the violence against Jews increased. Assault teams of the Dutch National Socialists hit and threw Jews off the trams and entered the Jewish quarter in order to smash windows and provoke Jews. Jews and non-Jews revolted against the assault teams, which led to street fights. During one of the fights a member of the National Socialist Movement was mortally injured. In retaliation the Germans temporarily closed off the Jewish quarter. Following this measure, they ordered the establishment of the Jewish Council. After an incident in the Jewish ice-cream parlour Koco, in which members of the Grüne Polizei were sprayed with ammonia, the Germans took additional measures.