The Soviet government's policies toward the Catholic Church were strongly influenced by Soviet Catholics' recognition of an outside authority as head of their church. As a result of World War II, millions of Catholics (including Greco-Catholics) became Soviet citizens and were subjected to new repression. Also, in the three republics where most of the Catholics lived, the Lithuanian SSR, the Byelorussian SSR and the Ukrainian SSR, Catholicism and nationalism were closely linked. Although the Roman Catholic Church was tolerated in Lithuania, large numbers of the clergy were imprisoned, many seminaries were closed, and police agents infiltrated the remainder. The anti-Catholic campaign in Lithuania abated after Stalin's death, but harsh measures against the church were resumed in 1957 and continued through the Brezhnev era.