The SS had two different parts. The "Allgemeine-SS" ("General SS") were the Nazis' police. The "Waffen-SS" ("Armed SS") were special units of soldiers in Nazi Germany's military. The Waffen-SS became known for fierce fighting and brutality against civilians and prisoners of war. Its units helped crush the Warsaw Ghetto Uprising, where Polish Jews tried to fight back against the Nazis. Waffen-SS units also killed many American prisoners of war during the Battle of the Bulge in 1944.