YouTube has terminated more than 400 channels on the video-sharing service for hosting comments from child predators.

The Google-owned service has also disabled the comments on tens of millions of videos featuring minors and reported the discovered illegal comments to law enforcement, a YouTube spokesperson told PCMag.

The company took action after YouTube creator Matt Watson posted a video on Sunday showing how pedophiles can use the platform to exchange contact details and links to child porn. The information can be posted in the comment sections for videos featuring minors, and can include time stamps that show the child exposing their bare legs or back.

YouTube's recommendation algorithms make the problem worse. Once you encounter one video carrying the pedophilia-related comments, YouTube will suggest more videos that carry the same illegal comments, according to Watson. "I can find this wormhole from a fresh YouTube account via innocuous videos within about five clicks," he added.

The videos have also been found carrying ads. In response, several companies including Nestle, Epic Games, and Disney, have reportedly suspended advertising on YouTube.

On Thursday, YouTube told PCMag that it's been cracking down on the child predatory comments by even removing dozens of legitimate videos posted with innocent intentions over fears the content could still be exploited.

"Any content — including comments — that endangers minors is abhorrent and we have clear policies prohibiting this on YouTube," a YouTube spokesperson said. "There's more to be done, and we continue to work to improve and catch abuse more quickly."

Nevertheless, it isn't the first time YouTube has faced problems with policing videos that contain comments from child predators. In 2017, YouTube videos of children were also attracting comments from pedophiles, which prompted some major brands to cancel advertising over the platform.

In its defense, YouTube said last year it terminated and reported 46,000 user accounts to authorities over child exploitation-related offenses. But it remains to be seen if YouTube can fully stop the problem. It can delete and suspend the affected videos channels, but child predators will likely try to infiltrate YouTube again and post the same illegal comments.

This article originally appeared on PCMag.com.