In the Polish areas annexed by Nazi Germany, as in the annexed regions of Slovenia and Austria, Nazi persecution of the church was intense; many clergy were targeted for extermination. Through his links to the German Resistance, Pope Pius XII warned the Allies of the planned Nazi invasion of the Low Countries in 1940. The Nazis gathered dissident priests that year in a dedicated barracks at Dachau, where 95 percent of its 2,720 inmates were Catholic (mostly Poles, with 411 Germans); over 1,000 priests died there.