The icon for the video sharing TikTok app is seen on a smartphone. Associated Press File Photo

The Justice Department sued TikTok on Friday, accusing the company of violating children’s online privacy law and running afoul of a settlement it had reached with another federal agency.

The complaint, filed together with the Federal Trade Commission in a California federal court, comes as the U.S. and the prominent social media company are embroiled in yet another legal battle that will determine if — or how — TikTok will continue to operate in the country.

The latest lawsuit focuses on allegations that TikTok, a trend-setting platform popular among young users, and its China-based parent company ByteDance violated a federal law that requires kid-oriented apps and websites to get parental consent before collecting personal information of children under 13.

TikTok did not immediately respond to a request for comment.

“This action is necessary to prevent the defendants, who are repeat offenders and operate on a massive scale, from collecting and using young children’s private information without any parental consent or control,” Brian M. Boynton, head of the Justice Department’s Civil Division, said in a statement.

The U.S. decided to file the lawsuit following an investigation by the FTC that looked into whether the companies were complying with a previous settlement involving TikTok’s predecessor, Musical.ly.

In 2019, the federal government sued Musical.ly, alleging it violated the Children’s Online Privacy Protection Act, or COPPA, by failing to notify parents about its collection and use of personal information for children under 13.

That same year, Musical.ly — acquired by ByteDance in 2017 and merged with TikTok — agreed to pay $5.7 million to resolve those allegations. The two companies were also subject to a court order requiring them to comply with COPPA, which the government says hasn’t happened.

In the complaint, the Justice Department and the FTC allege TikTok has knowingly allowed children to create accounts and retained their personal information without notifying their parents. This practice extends to accounts created in “Kids Mode,” a version of TikTok for children under 13, Justice said in a news release explaining the lawsuit.

The two agencies allege the information collected included activities on the app and other identifiers used to build user profiles. They also accuse TikTok of sharing the data with other companies — such as Meta’s Facebook and an analytics company called AppsFlyer — to persuade “Kids Mode” users to be on the platform more, a practice TikTok called “re-targeting less active users.”

The complaint says TikTok also allowed children to create accounts without having to provide their age, or obtain parental approval, by using credentials from third-party services. It classified these as “age unknown” accounts, which the agencies say have grown into millions.

After parents discovered some of their children’s accounts and asked for them to be deleted, federal officials said their requests were not honored. In a news release explaining the lawsuit, Justice said the alleged violations have resulted in millions of children under 13 using the regular TikTok app, allowing them to interact with adults and access adult content.

In March, a person with the matter had told the AP the FTC’s investigation was also looking into whether TikTok violated a portion of federal law that prohibits “unfair and deceptive” business practices by denying that individuals in China had access to U.S. user data.

Those allegations were not included in the complaint, which is seeking civil penalties and injunctive relief.