In the fast-changing digital world, companies are looking for new marketing tactics to reach their audiences. Many of them have turned to a practice known as “influencer” marketing, in which YouTube and Instagram personalities are paid for using or talking up a product on their social-media channels.

Now, a coalition of advocacy groups is urging the Federal Trade Commission to crack down on a specific subset of these marketing messages: the ones aimed at children.

The advocates said they planned to file a complaint Friday with the Federal Trade Commission asking the agency to take enforcement action against Google, Disney’s Maker Studios and three other companies for what they alleged was the “unfair and deceptive practice” of aiming influencer ads at children. The advocacy groups — which include Center for Digital Democracy, Campaign for a Commercial-Free Childhood and Public Citizen — also urged the federal agency to issue policy guidance on the matter.

Influencer advertising is a multibillion-dollar industry, and it is used to peddle all sorts of products, including fashion, beauty and cooking items. But advocates say these tactics are problematic when they are used to market toys, snacks and other goods to children.

“Owing to their immature cognitive development children — especially younger children — have difficulty differentiating between content and advertising,” the complaint reads.

The advocacy groups provide examples of content that they say violate federal law prohibiting deceptive advertising. In some, children are seen unboxing new toys from the likes of Lego. In another, a brother-and-sister YouTube duo are seen sampling 20 flavors of Pringles potato chips. That video has more than 27 million views on YouTube.

There was no immediate response to emails or phone calls seeking comment from two companies named in the complaint: Collab and WildBrain. Maker Studios and DreamWorks’s AwesomenessTV declined to comment because they had not viewed the complaint.

YouTube, the video site where much of this content is viewed, is a division of Google. The other companies that are named are involved in the production or distribution of content that is made for children.

A spokeswoman for YouTube told The Washington Post: “YouTube believes that creators should be transparent with their audiences if their content includes paid promotion of any kind. As our long-standing policy makes clear, anyone uploading videos to YouTube has a legal obligation to disclose to YouTube and their viewers if a video contains paid promotion.”

The advocacy groups, though, are not simply pushing for clearer disclosure around marketing aimed at children; they argue it should be avoided altogether.

YouTube also said that videos with disclosed endorsements are restricted from YouTube Kids, a separate app which is tailored to young audiences.

“We haven’t received a copy of the complaint yet, but we are very interested in reviewing it,” said Jessica Rich, director of the FTC’s Bureau of Consumer Protection. “The FTC has been very concerned about deceptive influencer ads, such as ads that don’t disclose that the influencers were paid for their endorsements. We’re also very concerned about protecting kids. We’ll take a careful look at the complaint.”

The FTC has taken several actions recently to try to bring more transparency to influencer marketing. Earlier this year, Lord & Taylor settled FTC charges that it had engaged in deceptive advertising. In 2015, the department store chain ran a social-media campaign in which 50 influencers were paid between $1,000 and $4,000 each to post photos of themselves wearing the same paisley-print dress. However, none of the influencers disclosed the sponsorship, as the law requires. This summer, Warner Bros. settled FTC charges that in an ad campaign for its “Middle Earth: Shadow of Mordor” video game, it did not go to great-enough lengths to ensure that influencers were disclosing that they’d been paid for their social-media posts.