I remembered there was a film about an alien group (or zombie) landed with a helicopter at somewhat like army base and start killing people. This movie haunted me a long time when I was in my childhood. After all the killing thing and near to the end of human race, it turned out that it was only a dream of a reporter, I thought so. And the next morning, it really happens and the film ends. Could anybody help to identify this film which I think was released in late 70's or early 80's.