Secretariat of the Communist Party of the Soviet Union the CPSU, who was also a Politburo member, was the leader of the Secretariat and of the Party. Dual membership in the Secretariat and the Politburo was in practice reserved for two or three very senior members of the Soviet leadership, and in the post-Stalin era (after March 1953) was a stepping-stone to ultimate power. The last five Soviet leaders (Nikita Khrushchev, Leonid Brezhnev, Yuri Andropov, Konstantin Chernenko and Mikhail Gorbachev) were all senior Secretaries before becoming First or General Secretaries. Additionally, Georgy Malenkov was briefly reckoned as the leader of the Party for a week after Stalin's death by
Polish prisoners-of-war in the Soviet Union after 1939 prison camps run by the NKVD. Of these, the Soviet authorities released 42,400 soldiers (mostly soldiers of Ukrainian and Belarusian ethnicity serving in the Polish army who lived in the former Polish territories now annexed by the Soviet Union) in October. The 43,000 soldiers born in West Poland, then under German control, were transferred to the Germans; in turn the Soviets received 13,575 Polish prisoners from the Germans. Poland and the Soviet Union never officially declared war on each other in 1939; the Soviets effectively broke off diplomatic relations when they withdrew recognition of the Polish government at the start