Despite being allies during World War II. The USSR and the US disagreed about the configuration of the post-war world while occupying most of Europe. The Soviet Union created the Eastern Bloc with the eastern European countries it occupied, annexing some as Soviet Socialist Republics and maintaining others as satellite states, some of which were later consolidated as the Warsaw Pact (1955–1991). The US and some western European countries established containment of communism as a defensive policy, establishing alliances such as NATO to that end.