France and Britain advised Czech acceptance of Sudeten autonomy. The Czech government refused and ordered a partial mobilisation in expectation of German aggression. Lord Runciman was sent by Chamberlain to mediate in Prague and persuaded the Czech government to grant autonomy. Germany escalated the dispute, the German press carrying stories of alleged Czech atrocities against Sudeten Germans and Hitler ordering 750,000 troops to the German-Czech border. In August, Henlein broke off negotiations with the Czech authorities. At a Nazi Party Rally in Nuremberg on 12 September, Hitler made a speech attacking Czechoslovakia and there was an increase of violence by Sudeten Nazis against Czech and Jewish targets.