Parents of four teenagers in Britain have filed a lawsuit against TikTok, who believe their children died after participating in a challenge released on the platform.

The lawsuit, filed in Delaware State Supreme Court, alleges that three boys and one girl died while attempting the so-called “blackout challenge.”

The deaths, according to the lawsuit, were “the foreseeable result of ByteDance’s planned decisions about addiction by design,” which were “intended to push children to maximize their engagement with TikTok by any means necessary.”

It further accused ByteDance, the parent company of TikTok, of “creating harmful addictions in every child” through its design.

Searches for videos or hashtags related to this challenge on TikTok have been blocked, the BBC reports. According to the company, the block is effective from 2020.

In addition, TikTok says it bans dangerous content or challenges and directs those looking for hashtags or videos to the Safety Center.

In 2021, TikTok said it would boost detection and enforcement around dangerous online challenges and reportedly blocked some searches for causing blackouts. However, it is facing several lawsuits and accusations from parents of children who died who claim the platform recommended harmful content to them.

The families’ lawsuit comes as questions remain about TikTok’s future in the U.S.

President Donald Trump signed an executive order shortly after taking office to extend the app’s operation in the country unless it is sold to another company.