The head of the artificial intelligence company that makes ChatGPT, Sam Altman, told Congress on Tuesday that government intervention “will be critical to mitigate the risks of increasingly powerful” AI systems.

“As this technology advances, we understand that people are anxious about how it could change the way we live. We are too,” OpenAI CEO Sam Altman testified at a Senate hearing Tuesday.

Altman proposed the formation of a U.S. or global agency that would license the most powerful AI systems and have the authority to “take that license away and ensure compliance with safety standards.”

His San Francisco-based startup rocketed to public attention after it released ChatGPT late last year. ChatGPT is a free chatbot tool that answers questions with convincingly human-like responses.

What started out as a panic among educators about ChatGPT’s use to cheat on homework assignments has expanded to broader concerns about the ability of the latest crop of “generative AI” tools to mislead people, spread falsehoods, violate copyright protections and upend some jobs.

And while there’s no immediate sign that Congress will craft sweeping new AI rules, as European lawmakers are doing, the societal concerns brought Altman and other tech CEOs to the White House earlier this month and have led U.S. agencies to promise to crack down on harmful AI products that break existing civil rights and consumer protection laws.

Sen. Richard Blumenthal, the Connecticut Democrat who chairs the Senate Judiciary Committee’s subcommittee on privacy, technology and the law, opened the hearing with a recorded speech that sounded like the senator, but was actually a voice clone trained on Blumenthal’s floor speeches and reciting a speech written by ChatGPT after he asked the chatbot to compose his opening remarks.

The result was impressive, said Blumenthal, but he added, “What if I had asked it, and what if it had provided, an endorsement of Ukraine surrendering or (Russian President) Vladimir Putin’s leadership?”

Blumenthal said AI companies ought to be required to test their systems and disclose known risks before releasing them, and expressed particular concern about how future AI systems could destabilize the job market.