<P> Propaganda was also considered an important foreign relations tool . International exhibitions, the distribution of media such as films, e.g.: Alexander Nevski, and journals like USSR in Construction, as well as inviting prominent foreign individuals to tour the Soviet Union, were used as a method of gaining international influence . </P> <P> Germany invaded Poland on September 1; the USSR followed on September 17 . The Soviets quelled opposition by executing and arresting thousands . They sent hundreds of thousands to Siberia and other remote parts of the USSR . Estimates varying from the figure over 1.5 million . to the most conservative figures using recently found NKVD documents showing 309,000 to 381,220. in four major waves of deportations between 1939 and 1941 . </P> <P> With Poland, including part of the old Prussian state, being divided between two powers, the Soviet Union put forth its territorial demands to Finland for a minor part of the Karelian Isthmus, a naval base at Hanko (Hangö) peninsula and some islands in the Gulf of Finland . Finland rejected the demands and on November 30, the Soviet Union invaded Finland, thus triggering the Winter War . Despite outnumbering Finnish troops by over 2.5: 1, the war proved embarrassingly difficult for the Red Army, which was ill - equipped for the winter weather and lacking competent commanders since the purge of the Soviet high command . The Finns resisted fiercely, and received some support and considerable sympathy from the Allies . But in the spring of 1940, the snows melted, and a renewed Soviet offensive compelled them to surrender and relinquish the Karelia Isthmus and some smaller territories . </P> <P> In 1940, the USSR occupied and illegally annexed Lithuania, Latvia, and Estonia . On June 14, 1941, the USSR performed first mass deportations from Lithuania, Latvia, and Estonia . </P>

Which is not a reason the soviet union wanted to maintain control over eastern europe