The U.S. Federal Trade Commission (FTC) has escalated its battle with TikTok over potential violations of children’s online privacy protections, Reuters reports. On Tuesday, the FTC stated it had referred a complaint against the popular video-sharing app and its Chinese parent company, ByteDance, to the Department of Justice.

The referral stems from an FTC investigation that uncovered evidence that TikTok may have violated laws governing data collection and privacy safeguards for underage users. A source previously told Reuters that the FTC could opt to file a lawsuit or seek a settlement to resolve the probe focused on TikTok’s information security and privacy practices.

Rather than pursue those routes, the FTC voted to hand off its findings to the Justice Department, stating that “the public interest” necessitated this forceful action, which the agency typically does not take. While light on specifics, the FTC believes TikTok and ByteDance either violated rules “or are about to.”

TikTok, with over 170 million American users, pushed back strongly. According to Reuters, the company said it has cooperated with the FTC for over a year and disputes allegations it claims are “factually inaccurate” or related to past issues already addressed.

The Justice Department referral is separate from concerns on Capitol Hill about potential Chinese government access to TikTok user data, which the company denies. TikTok is also challenging a new U.S. law requiring its Chinese owners to sell or face a nationwide ban in 2024.