The ghetto uprisings during World War II were a series of armed revolts against the regime of Nazi Germany between 1941 and 1943 in the newly established Jewish ghettos across Nazi-occupied Europe. Following the German and Soviet invasion of Poland in September 1939, Polish Jews were targeted from the outset. Within months inside occupied Poland, the Germans created hundreds of ghettos in which they forced the Jews to live. The new ghettos were part of the German official policy of removing Jews from public life. The combination of excess numbers of inmates, unsanitary conditions and lack of food resulted in a high death rate among them. In most cities the Jewish underground resistance movements developed almost instantly, although ghettoization had severely limited their access to resources. The ghetto fighters took up arms during the most deadly phase of the Holocaust against the Nazi plans to deport all prisoners – men, women and children – to camps, with the aim of their mass extermination.