By Nikhila Natarajan

New York, Oct 1 (IANS): US lawmakers blasted Facebook for three hours over the tech giant's handling of internal research that showed how its Instagram photo sharing platform was wrecking teens and weaponising "children's vulnerability".

Bombshell revelations in September first reported by The Wall Street Journal have set off alarm bells yet again around Facebook's hold over young audiences. The newspaper reported that for the last three years, Facebook has been studying how its photo-sharing app affects millions of young people on its platform, especially teenage girls.

Facebook witness Antigone Davis, head of global safety at the company, had a hard time playing defence. Davis insisted that the research on Instagram's impact on young people "is not a bombshella because it does not prove causality.

Shock and anger across party lines marked the hearing on Thursday as the Facebook spin room struggles to hold out against its biggest scandal after the Cambridge Analytica firestorm in 2016.

Few days ago, Facebook put on hold its kids' version of Instagram - targeted initially at tweens. A Facebook whistleblower will be sitting down for a CBS' "60 Minutes" show on Sunday. This crisis is not going away for Facebook anytime soon.

The gloves are off, the reactions Thursday were deeply personal. Five moments of fierce bipartisan pushback capture the battle-ready mood in US Congress - where it concerns protections for young people navigating digital platforms.

Senator Richard Blumenthal: "This research is a bombshell. It is powerful, gripping, riveting evidence that Facebook knows of the harmful effects of its site on children, and that it has concealed those facts and findings. I don't understand how you can deny that Instagram is exploiting young users for its own profit."

Senator Ed Markey: "Instagram is that first childhood cigarette meant to get teens hooked early. Facebook is just like Big Tobacco, pushing a product they know is harmful to the health of young people.

"Well let me just say this we're talking about 12 year olds. We're talking about nine year olds. If you need to do more research on this, you should fire all the people who you've paid to do your research up until now because this is pretty obvious and it's pretty obvious every mother and father, in our country because all recent scientific studies by child development experts found that not getting enough likes on social media significantly reduces adolescent's feelings of self self worth."

Senator Marsha Blackburn: "You've lost the trust, and we do not trust you with influencing our children. They (parents) also don't want Facebook collecting data on their children because - call them whatever you want, tweens, teens, young adults -A the bottom line is these are children. Their children, and you and Mr. Zuckerberg, both of you being parents should understand that Facebook has both a legal and a moral obligation to forgo collecting and using children's data."

Senator Amy Klobuchar: "You guys published your quarterly revenues. We have them on different countries right - how much money you make, we got that information. And so I'm trying to figure out if it includes Instagram, I'm trying to figure out if it includes kids which I assume it does, and I will keep pursuing it another way, when you estimate the lifetime value of a user, you must do that because I know your profit model and how it works now after years of taking on this monopoly dominant platform issue. What do you estimate the lifetime value of a user is for kids who start using Facebook products before age 13?"