In August 1939, to implement the first phase of this policy, Germany's Nazi government under Hitler's leadership staged the Gleiwitz incident, which was used as a "" for the invasion of Poland the following September. Nazi forces used concentration camp prisoners posing as Poles on 31 August 1939, to attack the German radio station Sender Gleiwitz in Gleiwitz, Upper Silesia, Germany (since 1945: Gliwice, Poland) on the eve of World War II in Europe. Poland's allies, the UK and France, subsequently declared war on Germany in accordance with their alliance.