The Soviets quickly began confiscating, nationalizing, and redistributing all private and state-owned Polish property.[9] During the two years following the annexation, the Soviets arrested approximately 100,000 Polish citizens across Kresy.[10] Due to a lack of access to the secret Soviet and Belorussian archives, for many years after the war the estimates of the number of Polish citizens deported to Siberia from the areas of Western Belorussia, as well as the number who perished under Soviet rule, were only estimated.[11] In August 2009, on the occasion of the 70th anniversary of the Soviet invasion, the authoritative Polish Institute of National Remembrance announced that its researchers reduced the estimate of the number of people deported to Siberia to 320,000 in total.