The Snow Devils (1967)

Starring Jack Stuart, Amber Collins, Rene Baldwin, Wilbert Bradley, Halina Zalewska
Directed by Anthony Dawson
(actor & director credits courtesy IMDB.com)

Commander Rod Jackson is assigned to investigate strange happenings in Earth's Arctic region, and discovers the legendary Yeti, who are in fact aliens intent on freezing the Earth, are to blame.

We have here a sort of followup to War Between The Planets, featuring many of the same actors and characters from that film, just as director Antonio Margheriti had earlier done with The Wild, Wild Planet and The War Of The Planets.  In fact all four films share similar sets, costumes, and effects, and Margheriti (credited as Anthony Dawson), directed all four.  This was the final film of the four to be released, and breaks up the formula refreshingly with the Yeti storyline, transposing much of the action to the frozen Arctic, before disappointingly resorting to a less-exciting space mission in the picture's final act.  I would have liked to have seen more done with the Yeti, probing into their planet's history and their leaders' motivations, but sadly this was not to be.