The number of victims includes 960,000 Jews (865,000 of whom were gassed on arrival), 74,000 ethnic Poles, 21,000 Roma, 15,000 Soviet prisoners of war, and up to 15,000 other Europeans. Those not gassed were murdered via starvation, exhaustion, disease, individual executions, or beatings. Others were killed during medical experiments.At least 802 prisoners tried to escape, 144 successfully, and on 7 October 1944, two Sonderkommando units, consisting of prisoners who operated the gas chambers, launched an unsuccessful uprising.