A global ban on developing artificially intelligent robot soldiers is needed to protect the future of mankind, a letter from hundreds of leading scientists including Stephen Hawking has warned.

More than 1,000 scientists and businessmen signed the open letter from the Future of LIfe Institute, calling on world leaders to prevent artificial intelligence (AI) technology from being used in a "global arms race".

Apple co-founder Steve Wozniak and SpaceX entrepreneur Elon Musk were also among the signatories of the letter, presented at a major conference in Argentina.

The letter warns that developing weapons beyond existing remote control drones, which could 'think' for themselves without human input, is "feasible within years" - and have the potential to become the "Kalashnikovs of tomorrow".

Launching a question and answer session on Reddit on the topic of AI, Prof Hawking said it was vital that scientists at the forefront of the technology keep the "human factor" at the "front and centre" of developments.