Before anyone asks for a source:

July 1942’s famous “Order No. 227,” better known as the “Not One Step Backward!” rule, which decreed that cowards were to be “liquidated on the spot.” Under this order, any troops who retreated were to be shelled or gunned down by so-called “blocking detachments”—special units who were positioned behind their own lines and charged with shooting any soldier who tried to flee. Stalin’s draconian orders were designed to increase the Red Army’s fighting spirit, but they weren’t empty threats. According to some estimates, Soviet barrier troops may have killed as many as 150,000 of their own men over the course of the war...