Mark Zuckerberg and Elon Musk trade shots and insults over artificial intelligence

It’s rare for Facebook Chief Executive Officer Mark Zuckerberg to interact publicly with other moguls online. When he does, it’s usually friendly and choreographed, like the time he asked Microsoft founder Bill Gates for help on a Harvard University commencement speech.

But with Elon Musk, the CEO of Tesla and Space Exploration Technologies Corp, it hasn’t been as cordial.

In a live video Q&A on Facebook Monday, Zuckerberg was asked what he thought about Musk’s calls for proactive regulation of artificial intelligence, before the robots become dangerously smarter than their creators and pose an existential threat to humanity.

Zuckerberg said he was optimistic about the technology, and that people shouldn’t call for a slowdown in progress with artificial intelligence.

Musk shot back on Twitter.

It’s not the first time the two have clashed publicly.