Originally Published: 03 MAY 23 14:20 ET

Updated: 03 MAY 23 15:04 ET

By Brian Fung, CNN

(CNN) -- The Federal Trade Commission on Wednesday accused Facebook-parent Meta of violating its landmark $5 billion privacy settlement and called for toughening up restrictions on the company, after alleging Meta has improperly shared user data with third parties and failed to protect children as it has promised.

The proposal to update the binding 2020 settlement with Meta marks a new front in the FTC's long-running battle with the social media company, which has included multiple lawsuits aimed at breaking up the tech giant or preventing it from growing larger.

The FTC said Meta should be banned from monetizing data it collects from younger users. It added that the company should be barred from releasing any new features or products until a third-party auditor determines the company's privacy policies do enough to protect users. It also called for new limitations on how Meta can use facial recognition technology.

If approved, the sweeping proposal could threaten the future of Meta's business, including its expansion into virtual reality.

In a statement on Wednesday, Meta spokesman Andy Stone called the FTC proposal "a political stunt" and vowed to contest the effort.

"Despite three years of continual engagement with the FTC around our agreement, they provided no opportunity to discuss this new, totally unprecedented theory," Stone said. "FTC Chair Lina Khan's insistence on using any measure -- however baseless -- to antagonize American business has reached a new low."

The FTC proposal comes as policymakers at all levels of government have increasingly blamed social media for furthering a mental health crisis among young people, prompting calls for strict regulations on how tech platforms can use the personal information of users under 18, target them with automated recommendations or seek to boost their engagement in other ways. Many of those proposals have taken the form of broad-based legislation, but the FTC proposal would represent a novel approach by amending a past consent order in connection with a single company that influences more than a billion users.

As part of the FTC's call for changes, the agency said Meta had misled the public about its compliance with the historic settlement that resolved allegations surrounding the Cambridge Analytica data fiasco, as well as prior agreements with the agency.

Meta had allowed personal information to leak to apps that users of the platform were no longer using, the FTC alleged. That data sharing, the FTC claimed, contrasted with Meta's public statements about how it cuts off a third-party app's access to Facebook users' information if the users stop using the third-party app for 90 days.

The FTC also alleged that multiple coding errors in a messaging app marketed to children, Messenger Kids, allowed users to connect to "unapproved contacts" in group video calls, and that the flaws went unresolved for weeks.

Those flaws meant parents could not control who their kids were speaking to on the app, in contrast to claims by Meta that they could, according to the FTC.

In addition to being a breach of Meta's prior settlements, the alleged violations surrounding Messenger Kids also ran afoul of a federal children's privacy law known as COPPA, the FTC said, because parents were not provided an opportunity to give Meta their consent before the company collected information on their kids.

Meta will have 30 days to respond to the proposed findings and changes, the FTC said, before the commission votes to finalize them. The FTC can unilaterally approve updates to the settlement, but Meta would have the opportunity to appeal that move in federal court, according to an agency fact sheet.

The FTC voted 3-0 to issue the proposed findings and changes, but one commissioner, Alvaro Bedoya, questioned whether the agency has the authority to impose such sweeping restrictions on Meta in light of the alleged violations.

In a statement, Bedoya said he was skeptical whether there was enough of a connection between Meta's alleged harms and the proposed remedies to legally sustain a complete ban on monetizing the data of young users.

"I look forward to hearing additional information and arguments and will consider these issues with an open mind," Bedoya said.