I'm searching for a movie that I just can't seem to find. I remember small bits of it, which I will try to explain:

It's a movie about some mutated dog like creatures.

I remember a scene where some people open a door and discovers a huge basment-ish room filled with those creatures.

I also remember a scene where some military (if I remember correctly) defends some kind of an outpost but it gets run over by the creatures.
In addition I remember specifically in that scene that some of the military guys tests some sensors on some automated guns because the creatures have some ability to like cloak themselves

There's also a scene where some kind of surgery where the (spine I believe) get's removed in order to make those creatures - if I'm not entirely wrong.

At the end of the movie, someone is walking alone (or with somebody) in an empty city and then they suddenly get attacked - which then ends to movie.

I really, really hope that someone know what that movie is called - because I would like to watch it again. Any clues will be much appreciated!!