Facebook and Instagram are suing four companies and three people in China for creating and promoting the sale of fake accounts, likes and followers on the social networks.
The lawsuit, filed in US federal court, alleges that the companies and people violated US intellectual property law by illegally using Facebook's and Instagram's trademarks and brands, Facebook said.
"By filing the lawsuit, we hope to reinforce that this kind of fraudulent activity is not tolerated -- and that we'll act forcefully to protect the integrity of our platform," Paul Grewal, Facebook's vice president and deputy general counsel of litigation, said in a blog post Friday.
Facebook didn't name the companies or people it's suing but said they also promoted fake accounts on Apple, Amazon, Google, LinkedIn and Twitter.
Since the 2016 US presidential election, social media companies have been under mounting pressure to do more to combat misinformation on their platforms.
Facebook didn't immediately respond to a request for comment.