The 1975 Helsinki Accords, which paved the way to the OSCE, established the "inviolability of frontiers" in Europe and afforded every sovereign country the right to decide on its alliances.
"The Helsinki principals say that every country has a right to join or not join any alliance so everybody has a right to do what is in their national interests," OSCE PA Secretary General Spencer Oliver said.
NATO’s expansion, which saw a boost in membership from 16 to 28 European nations after the end of the Cold War, in addition to plans to place heavy weaponry in Eastern Europe and the Baltic region, is seen in Moscow as a threat to national security.
Relations between Russia and the West have been in a downward spiral since the Crimean referendum and the start of the Ukrainian conflict, with the West accusing Russia of direct involvement in both affairs. The Kremlin maintains that the Black Sea peninsula’s plebiscite reflected the will of its population and the conflict in Ukraine is an internal matter that Moscow has no part in.