Facebook is considering developing a version of Instagram for children below the minimum age required to use its flagship image-sharing app, as originally reported by BuzzFeed News in March.

The 44 attorneys general have condemned these plans in a joint letter, arguing that such early exposure to social media is harmful for children’s health and mental wellbeing. They said that Facebook has historically failed to address serious harms such as invasions of children’s privacy, despite their claims that its services have strict privacy controls.

“Use of social media can be detrimental to the health and wellbeing of children, who are not equipped to navigate the challenges of having a social media account,” they wrote. “Further, Facebook has historically failed to protect the welfare of children on its platforms.”

They cited research suggesting a link between Instagram use and suicide ideation; anxiety about being socially excluded; bullying, and body image problems (exacerbated by inappropriate ad targeting). They also argued that children under the age of 13 are not yet capable of navigating this sort of social media platform safely, making them very vulnerable.

Children are “simply too young to navigate the complexities of what they encounter online, including inappropriate content and online relationships where other users, including predators, can cloak their identities using the anonymity of the internet,” the letter said.

The attorneys general noted that Facebook’s Messenger Kids app, which is intended for children between six and 12 years of age, contained a “significant design flaw that allowed children to circumvent restrictions on online interactions and join group chats with strangers that were not previously approved by the children’s parents”. US data protection regulations are much stronger for minors under the age of 13, with the 1998 Children’s Online Privacy Protection Act restricting how personal data of children can be collected and used. Some of the most popular social media platforms, including TikTok and YouTube, have been accused of violating this law.

“It appears that Facebook is not responding to a need, but instead creating one, as this platform appeals primarily to children who otherwise do not or would not have an Instagram account. In short, an Instagram platform for young children is harmful for myriad reasons. The attorneys general urge Facebook to abandon its plans to launch this new platform,” the letter concluded.

The letter was signed by Republican and Democrat attorneys-general from 40 states, including Massachusetts, New York, Texas and California. They were joined by the attorneys-general of the District of Columbia, Guam, Puerto Rico and the Northern Mariana Islands.

In April, the Campaign for a Commercial-Free Childhood urged Facebook to scrap plans for the app, arguing that the platform would put minors at “great risk”.

A Facebook spokesperson said the company has “just started exploring a version of Instagram for kids” and that it is committed to not showing adverts in any Instagram platform for minors: “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 [US] attorneys general.”