A jury has found Meta and YouTube liable in a first-of-its-kind lawsuit that aimed to hold social media platforms responsible for harm to children using their services.

A lawsuit against YouTube from the family of an American college student who was killed by Islamic State gunmen in Paris in 2015 is at the center of a closely watched Supreme Court case being argued Tuesday.

The fine is said to be between $150 million and $200 million, according to reports from Politico and The Wall Street Journal. Google owns YouTube. The FTC and the Department of Justice are also said to have divided up oversight of Google, Facebook, Apple and Amazon. "The FTC must demand structural change at Google & other tech companiesnot just financial penalties," Sen. Richard Blumenthal, a Democrat, wrote on Twitter Friday. Earlier this week, Google launched a separate website for its YouTube Kids service.

"Nothing is more important than making sure that children are protected on our platform," Neal Mohan, YouTube's chief product officer, told CNN Business at VidCon. It doesn't sound like YouTube would go as far as moving all children's content to its more heavily moderated YouTube Kids app. "Content that's violative of our community guidelines, we will remove from our platform as quickly as possible," he said. Mohan also said on stage that YouTube is removing more harmful content and reducing recommendations on content it considers "borderline." "This work is just as critical to the future of the YouTube community as any product launch."