During the interwar era, practically all of the Balkan governments fell to communist revolutions. Mostly from insurrections supported by their neighbours and the Soviet Union. Eventually they formed an alliance for mutual defence, the South European Pact, which joined the Eurasian Axis during WW2. Originally The Danubian Federation was also part of this group, though it was occupied by German forces during the war and its monarchy restored, later joining the North Atlantic Treaty Organisation (NATO).
The following nations are members of SEUROP:
- The Socialist Republic of Turkey
- The Socialist Federal Republic of Yugoslavia
- The People's Republic of Bulgaria
- The Socialist Republic of Romania
- The Democratic People's Hellenic Republic
- The People's Republic of Albania
Additionally, SEUROP, shares a defensive agreement with the Soviet-dominated Moscow Pact (MTO). The only nation that is a part of both organisations is The Socialist Republic of Turkey.