A group of leading tech leaders, including British scientist Stephen Hawking and Apple co-founder Steve Wozniak, on Tuesday issued a stern warning against the development of so-called killer robots. “The key question for humanity today is whether to start a global AI (artificial intelligence) arms race or to prevent it from starting,” they wrote. “If any major military power pushes ahead with AI weapon development, a global arms race is virtually inevitable,” the letter continued. “The deployment of such systems is — practically if not legally — feasible within years, not decades,” the letter said. The letter was presented at the opening of the 2015 International Joint Conference on Artificial Intelligence in Buenos Aires.