Okay, first of all, I was very young when I first saw this movie. I must have been all of ten years old. At that time, I thought it was pretty neat... two alien races conducting a discrete little war on Earth, unbeknownst to us mere Earthlings. When an alien agent kills another, they turn a key in the other agent's navel, and *sizzle* the corpse disintegrates. Decent suspense throughout, but remember ... we're talking a made-for-TV movie from 1970, no big-budget special effects.
What I find most amusing now is realizing who was in the movie .. Angie Dickenson, Daniel J. Travanti and LLOYD BRIDGES ... The Late Great Lloyd was very good in this, as an agent trying to protect a human woman (Dickenson) who had gotten caught up in the war, purely by accident.
I have no idea if this movie is available anywhere ... I'd like to see it again. No blockbuster of a movie, but it was fun.