The Axis powers invaded the Kingdom of Yugoslavia on 6 April 1941. The country surrendered 11 days later, and the government fled abroad, ultimately relocating to London. Nazi Germany, Fascist Italy, Bulgaria and Hungary annexed parts of the country. The remaining territory was broken up: most of it was organised as the Independent State of Croatia (NDH), a puppet state garrisoned by German and Italian forces, while the capital Belgrade remained in the German-occupied Territory of the Military Commander in Serbia. The USSR, still honouring the Molotov–Ribbentrop Pact, broke off relations with the Yugoslav government and sought, through its intelligence assets, to set up a new Communist organisation independent of the KPJ in the NDH. The USSR also tacitly approved the restructuring of the Bulgarian Workers’ Party. In particular, the party's new organisational structure and territory of operation were adjusted to account for annexation of Yugoslav territories by Bulgaria. The USSR only reversed its support for such actions in September 1941—well after the start of the Axis invasion of the USSR—after repeated protests from the KPJ.