The Treaty of Versailles reduced the territory of Bulgaria, but did not resolve any of the territorial conflicts in the Balkans. It created a powerful new state, Yugoslavia, next to Bulgaria, which claimed the Macedonian territories which Bulgaria felt belonged to it. It resulted in a flood of Bulgarian refugees out of the Yugoslavian part of Macedonia, Thrace, and of Greek refugees out of Bulgaria, and created tensions which would help lead to Bulgaria and the United States being on opposite sides in the Second World War.