During World War II, the Soviet Union occupied and annexed several countries effectively handed over by Nazi Germany in the secret Molotov–Ribbentrop Pact of 1939. These included the eastern regions of Poland (incorporated into two different SSRs), as well as Latvia (became Latvian SSR), Estonia (became Estonian SSR), Lithuania (became Lithuanian SSR), part of eastern Finland (became Karelo-Finnish SSR) and eastern Romania (became the Moldavian SSR and part of Ukrainian SSR). Apart from the Molotov–Ribbentrop Pact and post-war division of Germany, the USSR also occupied and annexed Carpathian Ruthenia from Czechoslovakia in 1945 (became part of Ukrainian SSR).