Elon Musk celebrated Labor Day with a dark premonition: Countries competing to be the best when it comes to artificial intelligence technology could “likely” be the case of WW3, according to the prolific technologist and entrepreneur.

Musk tweeted the sentiment on Monday, apparently inspired by recent events around North Korea and its apparent hydrogen bomb tests, as revealed by some follow-up comments with his Twitter followers.

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

Russia, China and “all countries w[ith] strong computer science” would soon be engaged in a race for AI supremacy, Musk said, responding to a story from The Verge about Russia leader Vladimir Putin making a comment about the global leader in AI becoming the overall leader of the world.

Musk doesn’t think that the countries developing AI will themselves necessarily trigger WW3 by conscious act, however – rather, he believes that one of the AIs developed in the technological arms race could actually launch the triggering attack, if it determines for itself that doing so is the best probably path towards becoming the clear global leader.

The OpenAI founder then went on to downplay the relative risk of nuclear war vs. the threat posed by an AI arms race, noting that nuclear launches should be “low on our list of concerns for civilizational existential risk.”

Musk said that one of the biggest risks around international state-driven pursuit of AI tech is that they aren’t bound by ordinary legal requirements. That, he pointed out, could help them avoid being bogged down by their own general tendency to lag behind private corporate interests in terms of the pace of innovation.

Govts don't need to follow normal laws. They will obtain AI developed by companies at gunpoint, if necessary. — Elon Musk (@elonmusk) September 4, 2017

In the past, Musk has spoken of the potential dangers of AI, and called in an “existential threat,” which is why he helped found both OpenAI (which aims to pursue development of artificial intelligence out in the open, where it can be properly vetted) and Neuralink (which aims to help us combine human brains with AI tech to prevent our becoming obsolete).

Critics have called Musk’s concerns a “mistake,” with some in the field of AI even going so far as to suggest he doesn’t properly understand that area of tech. Musk clearly hasn’t been deterred from his beliefs by critics, however.