ByteDance Ltd.’s TikTok is being targeted by a group of states seeking to determine whether the social media platform is being improperly marketed to children.

The states are investigating how TikTok promotes itself to younger users, including techniques to increase time spent on the platform and frequency of use, Massachusetts Attorney General Maura Healey said Wednesday. She is co-leading the probe with California, Florida, Kentucky, Massachusetts, Nebraska, New Jersey, Tennessee and Vermont.

“As children and teens already grapple with issues of anxiety, social pressure and depression, we cannot allow social media to further harm their physical health and mental well-being,” Healey said in a statement. “State attorneys general have an imperative to protect young people and seek more information about how companies like TikTok are influencing their daily lives.”

TikTok issued a statement saying, “We care deeply about building an experience that helps to protect and support the well-being of our community, and appreciate that the state attorneys general are focusing on the safety of younger users. We look forward to providing information on the many safety and privacy protections we have for teens.”

The probe was announced less than four months after a group of U.S. state attorneys general said they are investigating Meta Platforms Inc.’s Instagram photo-sharing app over its efforts to engage children and young adults. In May, 44 attorneys general urged Chief Executive Officer Mark Zuckerberg to drop the project. The company paused work on its Instagram Kids site in September after the Wall Street Journal reported that Facebook consistently played down its own research that the app can harm the mental well-being of its youngest users.

Texas Attorney General Ken Paxton said last month that he is probing TikTok for “potential facilitation of human trafficking and child privacy violations” as well as other possibly unlawful conduct.