Clashes began when units of the Assault Guard (Guardia de Asalto) – under the control of police chief Eusebio Rodríguez Salas and under the influence of the USSR-backed Communist Party of Spain and its local wing, the Unified Socialist Party of Catalonia (PSUC) – attempted to take over an anarchist-run telephone building in Barcelona. This was part of a series of similar appropriations by the Catalan government of worker-controlled industries at the behest of the USSR to crush anti-Stalinist labor forces