Meta Platforms (META) on Thursday announced a lawsuit against a Hong Kong-based company that has managed to work around the social media giant’s advertising detection technology to promote AI-powered explicit apps.

The Facebook and Instagram parent said it is suing Joy Timeline HK Limited, which owns a slate of apps called CrushAI, one of which allows users to take a picture of a person and use AI technology to make the image sexually explicit. The lawsuit was filed in Hong Kong, where Joy Timeline is based, Meta said.

The company behind the so-called “nudify” app continued to circumvent Meta’s ad review process after previous ads for the service had been removed from Meta’s platforms, Meta said.

Meta also said it was revamping its detection technology to catch more ads that may not feature explicit content like nudity in its ads but are still promoting a service that violates Meta’s rules.

The move comes after Meta received a letter from Illinois Senator Dick Durbin earlier this year, who asked Meta to answer for how it safeguards against these types of ads. The letter cited a report from the tech news outlet 404 Media, who found that an estimated 90% of traffic to CrushAI’s apps were coming from ads it had placed on Meta’s platforms.

Joy Timeline did not immediately respond to a request for comment.

The suit is the second against an AI company in as many days, coming a day after Disney (DIS) and Universal teamed up to sue AI image generation company Midjourney, alleging the company has made millions in revenue by violating the copyrights of their properties like “Star Wars” and Marvel Comics.