Elon Musk has said again that artificial intelligence could be humanity’s greatest existential threat, this time by starting a third world war.

The prospect clearly weighs heavily on Musk’s mind, since the SpaceX, Tesla and Boring Company chief tweeted at 2.33am Los Angeles time about how AI could led to the end of the world – without the need for the singularity.

China, Russia, soon all countries w strong computer science. Competition for AI superiority at national level most likely cause of WW3 imo. — Elon Musk (@elonmusk) September 4, 2017

His fears were prompted by a statement from Vladimir Putin that “artificial intelligence is the future, not only for Russia, but for all humankind … It comes with colossal opportunities, but also threats that are difficult to predict. Whoever becomes the leader in this sphere will become the ruler of the world.”

Hashing out his thoughts in public, Musk clarified that he was not just concerned about the prospect of a world leader starting the war, but also of an overcautious AI deciding “that a [pre-emptive] strike is [the] most probable path to victory”.

He’s less worried about North Korea’s increasingly bold nuclear ambitions, arguing that the result for Pyongyang if they launched a nuclear missile “would be suicide” – and that it doesn’t have any entanglements that would lead to a world war even if it did. His view is that AI is “vastly more risky” than the Kim Jong-un-led country.

Musk’s fear of AI warfare has been a driving force in his public statements for a long time. Last month, he was one of more than 100 signatories calling for a UN-led ban of lethal autonomous weapons.

“Once developed, lethal autonomous weapons will permit armed conflict to be fought at a scale greater than ever, and at timescales faster than humans can comprehend,” the letter read. “These can be weapons of terror, weapons that despots and terrorists use against innocent populations, and weapons hacked to behave in undesirable ways.

“We do not have long to act. Once this Pandora’s box is opened, it will be hard to close.”