– More than a dozen children’s advocacy groups on Thursday accused Facebook of knowingly deceiving children into racking up fees from games on its social network, the latest in a string of complaints against the company sent to federal regulators.

The groups called on the Federal Trade Commission (FTC) to investigate whether Facebook violated consumer protection and child privacy laws by duping children into making in-app purchases in games like Angry Birds, PetVille and Ninja Saga, and then making it nearly impossible for children or their parents to seek refunds. The accusation stems from a 2012 lawsuit.

The complaint, filed by 17 groups including Common Sense Media, Campaign for a Commercial Free Childhood and the Center for Digital Democracy, says the purchases were often done without a parent’s permission. In some cases, they amounted to hundreds or thousands of dollars.

“Facebook’s exploitative practices targeted a population universally recognized as vulnerable — young people,” the groups said in the complaint.

The children’s advocacy groups said they hoped their complaint would continue a drumbeat of pressure for Facebook to take more forceful steps to change its business practices oriented toward children.

“This is a pattern of behavior,” said James Steyer, chief executive of Common Sense Media. “Facebook has a moral obligation to change its culture towards practices that foster the well-being of kids and families, and the FTC should ensure Facebook is acting responsibly.”

Facebook and the FTC did not immediately respond to requests for comment.

Details about the in-app purchases came from court documents that were unsealed at the request of the Center for Investigative Reporting, a nonprofit journalism organization. The documents were part of a class-action lawsuit brought in 2012 and settled in 2016 for an undisclosed sum.

The 135 pages of unsealed documents included internal corporate memos and e-mails in which Facebook employees encouraged game developers to create features that would get children to make credit card charges while playing games. In many cases, the children did not realize that their parents’ credit cards were attached to the games or that they were spending real money, the consumer groups argued in their complaint.

The FTC polices consumer fraud, deception and unfair practices and is well versed in the issue of in-app purchases.

In 2013, the agency started an investigation into major charges by children using in-app purchases for things like “gold coins” in smartphone games. The FTC reached a $32.5 million settlement with Apple and a $19 million settlement with Google over accusations that children were deceived into making such purchases and that the companies did not properly disclose to parents that they were being charged for their children’s purchases.