NEW YORK (CBSNewYork) – Facebook is under fire over a new app.

Last month, Facebook launched Messenger Kids for children under the age of 13. Now, some are calling on the social media site to pull the plug.

READ MORE: Sneak Peek: Lincoln Center Plaza Transformed Into Green Space For Outdoor Summer Performances

When CBS2 first reported about the app in early December, reaction was mixed.

“Yeah, it seems fun and cool,” one boy said.

“No, I like to keep their innocence as long as possible,” a father added.

Now, a group of 100 childhood experts and advocates want it deleted. Led by the Boston-based Campaign for Commercial-Free Childhood, psychiatrists, pediatricians, educators and one children’s music singer have teamed up to send Facebook CEO Mark Zuckerberg a letter.

They also launched an online petition, saying in part, “Research shows that excessive social media use is already harming adolescents and teens. Younger children are even less equipped to deal with the interpersonal challenges and addictive power of social media. Kids need time and space to experience the physical world and develop healthy face-to-face relationships.”

The app works like this: To set it up, a parent has to use his or her own Facebook account. Then, the parent selects the child’s friends and approves new friend requests as they come in. There are no ads and children can’t make purchases.

READ MORE: Stimulus Check Update: Is A Fourth Relief Payment In Your Future?

“Look, I wish they were right. I wish there was no need for kids to be on social media for all the negative reasons that they site in their research. The reality is kids are on social media. Their parents are on social media. Their cousins, their friends,” Co-founder and CEO of Headliner Labs Caroline Klatt said. “Social media has become such a core part of what we all do that expecting kids to stay away from it and removed from it I think is pretty naive.”

Klatt develops mobile messaging technology.

“So if they’re going to be on social media, it’s fantastic that they can be on a safer version of it,” she added.

Parents CBS2’s Alice Gainer spoke with Tuesday said they have no problem with Messenger Kids, as long as they are the ones in control.

“I think nowadays kids want to use Facebook. And if they are supervised by the parents, there is no problem,” one woman said.

“They’re already exposed to all types of social media already as it is. Even in school some of the curriculum calls for them to have internet access,” another added.

Many said it’s ultimately up to the parent to grant access to the app or not.

MORE NEWS: NASA Rocket Launch Friday Night Could Be Visible In Tri-State Area

In a statement, Facebook said the app helps parents and children chat in a safer way. According to one app analytics firm, the app has been downloaded about 80,000 times since it launched.