The film was initially banned in France on political grounds. An article noted that France had also banned Soviet films with political themes, and that "a number of European countries are sensitive to films with political themes and refuse them exhibition permits, rather than rouse the ire of either the U.S. or Russia."
The scene of the attack on the first island was taken from the movie Requins d'acier (1943), particularly the ammo exploding in the depot and the burning fuel cascading over the short cliff into the sea.
According to actor Gene Evans, he was asked by director Samuel Fuller to help Bella Darvi with her dialogue. Others, especially star Richard Widmark, disliked her and Fuller convinced the reluctant Evans that Darvi liked him enough to make it a plausible idea. Darvi was happy with Evans' coaching and gave him a birthday present of silver pieces monogrammed 'DFZ'. Evans later found out that Darvi was Zanuck's mistress, which is why she got the part.
This was Twentieth Century-Fox's fifth CinemaScope production.
This marked the feature film debut of Darryl F. Zanuck's muse Bella Darvi, whose stage surname was a composite of the first names of Zanuck and his wife Virginia.