WASHINGTON (NEXSTAR) — Executives of the some of the biggest tech companies were on Capitol Hill Wednesday with senators to share their insights about artificial intelligence technology.

Elon Musk, Mark Zuckerberg and Bill Gates were some of the big names at the meeting, which was closed to the public. In total, about two dozen executives were invited to speak.

Musk, CEO of Tesla, likely delivered the most alarming message. He warns the technology may pose a risk to civilization.

“There is some chance, above zero, that AI will kill us all. I think it’s low, but there is some chance,” Musk said.

The remarks came after a closed-door meeting with senators Wednesday. Musk was among the tech leaders there urging Congress to act.

“I think it’s clear that there’s a strong consensus, overwhelming consensus that there should be some AI regulation, that it would be in the best interest of the people to do so,” Musk said.

“This is the hardest thing I think we’ve ever undertaken,” said Senate Majority Leader Chuck Schumer, D-NY.

Schumer arranged the meeting, which also included civil rights and labor leaders. He admits passing sweeping regulations will be difficult and take time.

“But we can’t be like ostriches and put our head in the sand because if we don’t step forward, things will be a lot worse,” said Schumer.

Among the vast list of concerns: job security, national security and data privacy.

“We need to figure out how to maximize the benefits and minimize the harms,” Schumer said.

Republican Sen. Mike Rounds of South Dakota said both sides want to move forward with caution.

“We have to have a regulatory prospect but we’re not ready to write the regs today. We’re not there,” said Rounds.

But not everyone left the meeting satisfied.

“They’re sitting at a big round table all by themselves. All of the senators are to sit there and ask no questions. That’s the setup,” said Sen. Elizabeth Warren, D-MA

Warren said congress should take bold action now.

“Let’s put something real on the table,” she said.

Schumer has not issued a specific timeline to call a bill to a vote. He says this issue isn’t going to be addressed in a matter of days or week, but nor should it be years.