The 27th Day (1957)

Synopsis
A locked-in-the-fifties science fiction film, The 27th Day begins with five different people from five different countries suddenly disappearing from view. They have been gently abducted by the agent (Arnold Moss) of a faraway dying planet, who gives each of the five earthlings a "killing capsule" that will destroy everything on Earth and allow the residents of the alien planet to re-colonize the planet--but which will be ineffective if not used after 27 days. In typical Cold War fashion, the representatives of the "good" countries (including Gene Barry) refuse to utilize the capsules, while the Soviets, (personified by Azemat Janti and Stefan Schnabel) intend to deploy the capsules for their own nefarious purposes. Their perfidy only results in the utter decimation of the USSR. ~ Hal Erickson, All Movie Guide