Elon Musk called for a “regulatory structure” for artificial intelligence after warning US senators about risks to civilization posed by the nascent technology.

The billionaire owner of X, formerly known as Twitter, was among more than 20 tech and civil society leaders attending a closed-door Senate summit Wednesday focused on AI. He later met privately with House Speaker Kevin McCarthy.

“When there is something that is a potential danger to the public you want to have some oversight,” Musk told reporters.

Musk, who’s also the chief executive officer of Tesla Inc., told senators they shouldn’t be worried about self-driving cars, for instance, but instead should focus their concerns on what he called deeper AI, a person in the room said. Deep AI is an apparent reference to deep learning, a type of artificial intelligence that teaches computers to process data in a way that imitates the human brain.

Musk, who spoke off-the-cuff, particularly raised concerns about data centers so powerful and big that they could be seen from space, with a level of intelligence that is currently hard to comprehend, the person said.

Among projects started by Musk, the world’s richest person, is an AI company, xAI.

On China, Musk recounted his earlier trip to the nation and said he raised the risks of deep AI and super intelligence with senior officials there.

Read more: Musk Believes China Is on ‘Team Humanity’ When It Comes to AI

Musk told reporters he didn’t talk directly to Mark Zuckerberg at the summit but that he would be up for a cage match with the chief executive officer of Meta Platforms’ Facebook “if he wants to.”