Ninja kill (1987)

"Gordon (Richard Harrison), the great ninja master faces the most desperate challenge of his life when he and his intrepid ally David, must answer to ninja law and do battle with a brutal horde of evil ninjas in order to foil an assassination plot. Led by the depraved criminal mastermind Stuart, an army of sadistic purple ninjas em-barks on a bloody killing spree in a campaign to seize control of the entire nation. As part of his heinous scheme, Stuart plans to assassinate a senator and replace him with a figurehead who will establish a base of oper-ations for the seductive and deadly beauty known as "Miss Littleton". The tension mounts to the breaking point as Gordon and David put their lives on the line to end the reign of terror!" - VHS Back of the box description. A Hong Kong cut and paste edit of the 1982 Thai film "จ้าวนรก" (Lord of Hell/Fire Chief) with new scenes with ninjas.