The U.S. Justice Department and the Federal Trade Commission (FTC) sued TikTok and its China-based parent company ByteDance on Friday over violations of the Children's Online Privacy Protection Act (COPPA). TikTok is one of the world's most popular social media platforms. The civil lawsuit was filed in a federal court in California.

COPPA bars website entities from collecting information from children under the age of 13 without notifying parents and obtaining parental consent. COPPA also requires offending websites to delete children's information upon the parents' requests.

In 2019, the government sued TikTok's predecessor, Musical.ly, for COPPA violations.

"Since then," the Justice Department said in a statement Friday, "the defendants have been subject to a court order requiring them to undertake specific measures to comply with COPPA."

TikTok and ByteDance remain under that compliance court order.

According to Friday's complaint, TikTok knowingly allowed children to create, view and share videos with adults and communicate with adults. The Justice Department said the defendants also "collected and retained a wide variety of personal information" from children without their parents' consent or knowledge.

The defendants also engaged in the same conduct on Kids Mode, a version of TikTok intended for children under 13, the complaint said.

Once parents discovered their children's accounts, the defendants "frequently failed to honor those requests" as the company "had deficient and ineffectual internal policies and processes for identifying and deleting TikTok accounts created by children," the complaint reported.

"TikTok knowingly and repeatedly violated kids' privacy, threatening the safety of millions of children across the country," said FTC Chair Lina Khan. "The FTC will continue to use the full scope of its authorities to protect children online — especially as firms deploy increasingly sophisticated digital tools to surveil kids and profit from their data."

Acting Associate Attorney General Benjamin C. Mizer said the Justice Department "is deeply concerned that TikTok has continued to collect and retain children's personal information despite a court order barring such conduct."

He said that by filing the lawsuit, the Justice Department is seeking "to ensure that TikTok honors its obligation to protect children's privacy rights and parents' efforts to protect their children."

Some material for this report came from The Associated Press.