The Mysterians 1957
Director: Ishirō Honda
Staring: Kenji Sahara, Momoko Kōchi, George Furness, Haruo Nakajima, Yumi Shirakawa, Akihiko Hirata, Takashi Shimura, Katsumi Tezuka, Ren Imaizumi, Susumu Fujita, Hisaya Ito
Aliens arrive on Earth and ask permission to be given a certain tract of land for their people to live on.
But when they are discovered to be invaders, responsible for the giant robot that is destroying cities, the armed forces attempt to stop them with every weapon available.
Enjoy the trailer then find out some facts and the making of it here.
https://youtu.be/ZKRqWf9w2e4