Facebook is facing increasing criticism over plans for a children’s version of Instagram.

Last week, 44 attorneys general asked Facebook CEO Mark Zuckerberg to scrap any plans to launch a photo-sharing app for children, arguing that children “are not equipped to navigate the challenges of having a social media account.”

On Tuesday, four lawmakers joined the call for Facebook to put aside ambitions to launch Instagram Kids.

“When it comes to putting people before profits, Facebook has forfeited the benefit of the doubt, and we strongly urge Facebook to abandon its plans to launch a version of Instagram for kids,” Sens. Ed Markey (D-Massachusetts) and Richard Blumenthal (D-Connecticut) and Reps Kathy Castor (D-Florida) and Lori Trahan (D-Massachusetts) stated.

Last month, Markey and the others asked Facebook to answer dozens of questions about the potential new service — including what data will be collected, and whether the service will be supported by targeted advertising.

On Tuesday, the lawmakers suggested Facebook’s answers were lacking.

“The company refused to make meaningful commitments about how it will ensure that its proposed Instagram Kids app does not harm young users’ mental health and threaten their privacy,” the lawmakers stated.

For its part, Facebook told the representatives it plans to “work in close consultation with safety, privacy, and child development experts” to develop the service.

The company also says it won’t show ads in a children’s version of Instagram.

But advocacy groups say concerns about Instagram’s effects on children go beyond paid ads on the service.

Instagram’s “relentless focus on appearance, self-presentation, and branding presents challenges to adolescents’ privacy and well-being,” more than 90 advocacy groups —  including the Campaign for a Commercial-Free Childhood, Center for Digital Democracy, Electronic Privacy Information Center, and creators of the documentary “The Social Dilemma” — said last month in a letter to Facebook.

Facebook currently doesn’t allow children under 13 on Instagram or Facebook.com, but many young children appear to use the services despite the companies’ official policies.

A spokesperson has said the company is working on new age-verification methods to prevent children from using the current version of Instagram.

The calls for Facebook to abandon Instagram Kids come as Silicon Valley companies are under increasing scrutiny over how they handle data — including children’s data.

On Tuesday morning, the Senate Commerce Committee’s consumer protection subcomittee addressed the upcoming service at the hearing, “Protecting Kids Online: Internet Privacy and Manipulative Marketing.”

Blumenthal, who chairs the subcommittee, elaborated on his objections to Facebook’s planned service.

“Facebook has not only failed to earn our trust, it has actively betrayed our trust in many respects,” Blumenthal said.

“Its practices with Messenger Kids — allowing strangers to chat with children — its other violations of trust, certainly argue powerfully against, now, Instagram Kids, so I hope that it will cancel its plan.”

Blumenthal also asked the hearing witnesses, including computer scientist and privacy expert Serge Egelman, whether Facebook should cancel plans for a children’s version of Instagram.

“Probably, yes,” Egelman replied. “The concern there, I think, is even if Instagram Kids is benign and isn’t collecting all of the data from kids, it’s another type of grooming behavior.”

“It’s locking them into the platform, so that when they turn 13, all their friends are on Instagram, now they’re locked in and need to continue using it, and now it does start collecting all of their data,” Egelman added. “And then they’re stuck making a choice. Do they abandon those social connections, or give up privacy?”