 The main obstacle to forming an alliance earlier was a long-standing territorial dispute over Vilnius (see "Żeligowski's Mutiny").The Lithuanian Activist Front ("Lietuvos Aktyvistų Frontas", or LAF) had cooperated with Nazi operations against Poles during the German occupation.In autumn 1943, the Home Army opened retaliatory operations against the Nazis' Lithuanian supporters, mainly the Lithuanian "Schutzmannschaft" battalions, the Lithuanian Territorial Defense Force, and the Lithuanian Secret Police, and killed hundreds of mostly Lithuanian policemen and other collaborators during the first half of 1944.