San Francisco, California - Meta agreed to pay US states as much as $16.7 billion and to impose sweeping new limits on how teenagers use Facebook and Instagram, according to a court filing on Wednesday that ends a landmark trial in California.

The proposed settlement, filed in federal court, would resolve claims by a coalition of US states that Meta deliberately engineered its platforms to hook young users, misled the public about the risks and unlawfully collected data from children under 13.

"Meta has agreed to make massive transformations that will reduce the risk of harm from its platforms – and will do it within months," California Attorney General Rob Bonta said in a statement.

He called the outcome "real change, real transparency, and real enforceable protections for children."

Justice Will Meta and states reach mid-trial settlement in landmark social media case?

The filing states that the agreement does not amount to an admission of liability or wrongdoing by Meta, which has consistently denied the allegations. It requires court approval to take effect.

The most far-reaching provisions are not financial, with Meta agreeing to a long list of new safeguards that will substantially change how the apps work for young people.

One change will switch on a nighttime block that by default locks teenagers out of Facebook and Instagram between midnight and 6:00 AM local time.

Teenage accounts will also be capped by default at two hours of cumulative daily use across Meta's apps.

The settlement ends the trial in its second week.

Instagram boss Adam Mosseri took the stand on Tuesday and admitted he touted newly launched safety tools for teens without disclosing low adoption rates from early testing several years ago.

Other witnesses testified over the past week that Meta knew the tools were not effective and even that they were "designed to fail."

Meta founder and chief executive Mark Zuckerberg had been expected to testify as well.