WASHINGTON (AP) — “Deepfake” videos pose a clear and growing threat to America’s national security, lawmakers and experts say. The question is what to do about it, and that’s not easily answered.

A House Intelligence Committee hearing Thursday served up a public warning about the deceptive powers of artificial intelligence software and offered a sobering assessment of how fast the technology is outpacing efforts to stop it.

With a crudely altered video of House Speaker Nancy Pelosi, D-Calif., fresh on everyone’s minds, lawmakers heard from experts how difficult it will be to combat these fakes and prevent them from being used to interfere in the 2020 election.

“We don’t have a general solution,” said David Doermann, a former official with Defense Advanced Research Projects Agency. “This is a cat and a mouse game.”

The videos are made using facial mapping and artificial intelligence. The altered video of Pelosi, which was viewed more than 3 million times on social media, gave only a glimpse of what the technology can do. Experts dismissed the clip, which was slowed down to make it appear Pelosi was slurring her words, as nothing more than a “cheap fake.”

Rep. Adam Schiff, D-Calif., the committee chairman, said the Pelosi video “demonstrates the scale of the challenge we face.” But he said he fears a more “nightmarish scenario,” with these video spreading disinformation about a political candidate and the public struggling to separate fact from fiction.

Doermann said the threat has grown worse due to the proliferation of what was once specialized technology. Creating convincing fabricated videos once required expensive equipment and software, but now “a high school student with a good computer” can do it, he said.