Several US groups advocating public and children’s health have urged the federal trade regulators to take action against social media giant Facebook for allegedly violating children’s privacy law.

The 18-member group led by the Campaign for a Commercial-Free Childhood (CCFC) on Wednesday said the groups have filed a complaint asserting that Facebook’s Messenger Kids, a controversial messaging application for children as young as five, collects kids’ personal information without obtaining verifiable parental consent, Xinhua reported.

Messenger Kids is the first major social platform designed specifically for young children, but Facebook’s parental consent mechanism does not meet the requirements of the Children’s Online Privacy Protection Act (COPPA), said CCFC, which called on the Federal Trade Commission (FTC) to probe Facebook and take action against it.

Facebook Messenger Kids’ privacy policy is incomplete and vague, because any adult user can approve any account created in the app and “even a fictional ‘parent’ holding a brand-new Facebook account could immediately approve a child’s account without proof of identity,” CCFC said.

It further accused Facebook of disclosing data to unnamed third parties for “broad, undefined business purposes.”

The CCFC said the advocacy groups have sent Facebook CEO Mark Zuckerberg a letter signed by over 100 experts and advocates earlier this year to ask him to remove Messenger Kids from its platform.

“Messenger Kids blatantly violates COPPA’s protections for children’s privacy by collecting children’s personal information without informed, verifiable parental consent,” said Jim Graves, staff attorney and clinical teaching fellow at the Institute for Public Representation at Georgetown University Law Center.

Facebook launched Messenger Kids on iOS last December to let kids under 13 chat with friends and family. The app was later expanded to Android users in the United States, Canada and other countries. The social media giant argued that the app displays no ads and lets parents approve who their children would message.

But critics have been skeptic about Facebook’s security measures in protecting children’s privacy, and have been pushing for its closure since its debut last year.