The 27th Day
Plot: Five individuals from five nations, including the USA, USSR, and China, suddenly find themselves on an alien saucer, where an alien gives each a container holding three capsules. The alien explains that no power on earth can open a given container except a mental command from the person to whom it is given, then anyone may take a capsule and, by speaking a latitude and longitude at it, cause instant death to all within a given radius: thus each of the five has been provided with the power of life and death