If any major military moves ahead with developing artificial intelligence weapons, a global arms race of robotic killing machines is virtually inevitable, according to an open letter that Stephen Hawking, Elon Musk and hundreds of other robotics researchers signed.

Autonomous weapons—or those not controlled by humans—include weapons like armed quad-copters that can search and kill people meeting at a certain place at a certain time. They don’t include cruise missiles or remotely piloted drones, which humans control.

“It will only be a matter of time until [autonomous weapons] appear on the black market and in the hands of terrorists, dictators wishing to better control their populace, warlords wishing to perpetrate ethnic cleansing. …” the letter from the Future of Life Institute warned of artificial intelligence being pursued as a means of violence.

Check out the full article here.

Image via Alec Meer under Flickr CC.