In the years before 1914 violent pogroms were directed against Jews, who were made scapegoats for the problems of the Russian Empire. The flight of Jews from the east, first to escape the violent prejudices unleashed periodically in Tsarist Russia and then to escape the upheavals in the aftermath of World War I, sharpened the anti-Semitism which was already to be found in the west of Europe [Source]
I am looking for a source to support the statements above.
Also, what else is considered to have played a role in the growth of international anti-semitism that was a precursor to the persecution of Jews by NS Germany?