Facebook’s plans to launch a version of Instagram for children under the age of 13 continues to get backlash. On Monday, 44 attorneys general signed a letter addressed to Facebook\n \n (FB) CEO Mark Zuckerberg, urging him to scrap plans for an Instagram intended for younger users, citing mental health and privacy concerns. The letter comes less than a month after child safety groups and Congress expressed similar concerns. “Use of social media can be detrimental to the health and well-being of children, who are not equipped to navigate the challenges of having a social media account,” the latest letter said. “Further, Facebook has historically failed to protect the welfare of children on its platforms. The attorneys general have an interest in protecting our youngest citizens, and Facebook’s plans to create a platform where kids under the age of 13 are encouraged to share content online is contrary to that interest.” Facebook claims such a service would give parents greater control over their children’s online activity. “As every parent knows, kids are already online. We want to improve this situation by delivering experiences that give parents visibility and control over what their kids are doing,” a Facebook spokesperson said in a statement to CNN Business. “We are developing these experiences in consultation with experts in child development, child safety and mental health, and privacy advocates. We also look forward to working with legislators and regulators, including the nation’s attorneys general. In addition, we commit today to not showing ads in any Instagram experience we develop for people under the age of 13.” The spokesperson also noted that Facebook is a founding sponsor of a new Digital Wellness Lab at Boston Children’s Hospital to better understand the effect of digital technology on kids. In March, Buzzfeed News obtained an internal Instagram memo stating the company has “identified youth work as a priority for Instagram” and was moving forward with plans to build a version specifically intended for kids. It came two days after a blog post from the company, titled “Continuing to Make Instagram Safer for the Youngest Members of Our Community,” which said it needed to do more to combat abuse, bullying and other issues that occur on the platform. During a Congressional hearing in March, Zuckerberg was asked about the company’s plans for building a version of Instagram for younger users. “I find that very concerning, targeting this particular age bracket, 13 and under, given the free services, how exactly will you be making money?” said Florida GOP Congressman Gus Bilirakis. “Or, are you trying to monetize our children, too, and get them addicted early?” Zuckerberg said the platform is still “early in our thinking” and “there is clearly a large number of people under the age of 13 who would want to use a service like Instagram.” Instagram doesn’t formally allow users under the age of 13 onto the platform. But because there is not a strict age verification, some younger users have accounts. While a more safety-forward service could in theory better suit that untapped audience, the letter from the attorneys general expressed great concern around privacy, noting children “may not fully appreciate what content is appropriate for them to share with others, the permanency of content they post on an online platform, and who has access to what they share online. They are also simply too young to navigate the complexities of what they encounter online,” the letter said. This wouldn’t be Facebook’s first time showing interest in developing a children version of one of its services. Its Messenger Kids messaging app targets users ages six to 12.