Actor Leo Gordon was also the screenwriter and had spent most of his career playing murderous outlaws, homicidal killers and assorted brutish and psychotic villains. His role here of Sgt. Krug was one of the few times he actually played a good guy.
American M3 halftracks, with skillfully altered bodies, impersonate German SdKfz 7's, which were much larger machines.
Technical advice and assistance for the film were provided by the 40th Armored Division ("Grizzly") of the California Army National Guard.
The part of Colonel Harker was offered to Dirk Bogarde, who passed.