The clauses of the Nazi-Soviet Pact provided a written guarantee of non-belligerence by each party towards the other, and a declared commitment that neither government would ally itself to, or aid, an enemy of the other party. In addition to stipulations of non-aggression, the treaty included a secret protocol that divided territories of Poland, Lithuania, Latvia, Estonia, Finland, and Romania, into German and Soviet "spheres of influence", anticipating "territorial and political rearrangements" of these countries. Thereafter, Germany invaded Poland on 1 September 1939. Soviet Union leader Joseph Stalin ordered the Soviet invasion of Poland on 17 September; one day after a Soviet-Japanese ceasefire at the Khalkhin Gol came into effect.[6] In November, parts of the Karelia and Salla regions in Finland were annexed by the Soviet Union after the Winter War. This was followed by Soviet annexations of Estonia, Latvia, Lithuania, and parts of Romania (Bessarabia, Northern Bukovina, and the Hertza region). Advertised concern about ethnic Ukrainians and Belarusians had been proffered as justification for the Soviet invasion of Poland. Stalin's invasion of Bukovina in 1940 violated the pact, as it went beyond the Soviet sphere of influence agreed with the Axis.[7]
