And they have all the technology they need to do it.
See This article
It's long so unless you love to read, I would recommend just skipping through it and focus on the sections with pictures. That would be the quickest way to get up to speed on it if you aren't already.
But autonomous Unmanned Arial Vehicles (UAVs) that don't need human direction. They just tell it to go kill. Same with everything else. And what of war itself when it is dehumanized ? It's like the Star Trek episode where two planets have computers on each planet and conduct virtual attacks and the determined casualties have to walk into suicide chambers. Nice and neat and disgusting.
They will have Artificial Intelligence (AI) software in these things that can learn. That software is available now. The learning part is the particularly scary part. It is easy to see how a learning robot will soon come to regard mankind as the main threat to the planet.
Even if they couldn't learn, they'd be hacked and reprogrammed. Elon Musk and Stephen Hawking are against this to the 10th power. Easy to understand why.
Say Hello to My Leeetle Friend....
These things are being built today in many forms.