SAN FRANCISCO — YouTube said Thursday it will turn off comments on nearly all videos featuring kids — potentially affecting millions of posts on the site — after reports last week that pedophiles were leaving inappropriate comments on innocuous videos of children.

The change comes as YouTube grapples with moderating content across its platform as concerns about hate speech, violence and conspiracy theories continue to plague it.

It will take YouTube several months to disable comments on all videos featuring minors, the company said. It already started the process last week when it turned off comments from tens of millions of videos.

Sponsors Pull Support Because of Inappropriate Comments

Advertisers including Nestle, AT&T, and Fortnite-maker Epic Games pulled ads from YouTube last week after the inappropriate comments about children were unearthed by a popular YouTuber and media reports. At least one company, Nestle, was satisfied with YouTube’s response and reinstated ads late last week.

A small number of channels which have videos featuring kids will be allowed to keep comments turned on. But they must be known to YouTube and must actively monitor the comments beyond the standard monitoring tools YouTube provides.

Turning off comments on such a large number of videos seems an “extreme reaction,” said eMarketer analyst Paul Verna. But the issue involves the safety of children, so it makes sense YouTube would want to act quickly, he said.

Comments aren’t the main focus of the video-publishing site, but turning them off will likely diminish the experience for many users and video creators, he said.

YouTube CEO Susan Wojcicki acknowledged the concerns Thursday, tweeting, “Nothing is more important to us than ensuring the safety of young people on the platform.”

Updated Automated Moderating System

The company said it has also released an updated version of its automated moderating system that it expects will identify and delete two times as many inappropriate comments.

YouTube, like Facebook, Twitter and other sites that allow user publishing, have faced increasing calls to monitor what appears on their sites and get rid of unsuitable content. The companies all say they have taken action to protect users. But issues keep popping up.

Concerns about YouTube comments weren’t even a top priority for advertisers and viewers a couple weeks ago, Verna said.

“It just makes you wonder, what’s the next thing that going to happen?”