In World War II, when the Red Army began its advance against Nazi Germany, Strong stayed in the rear following the soldiers through Warsaw, Łódź and Gdańsk. Her overtly pro-Chinese Communist sympathies, which had been fostered by her visits to China in 1925 and until 1947 in which she interviewed Chinese Communist leaders like Mao Zedong, may have led to her "arrest, imprisonment and expulsion" from the USSR in 1949, reportedly claiming she was an "American spy," a charge which reportedly was repeated years later, in 1953, by the Soviet newspaper "Izvestia".