A leading anti-bullying charity has condemned a viral video which shows an American teenager named Sharkeisha sucker-punching her victim.
The Anti-Bullying Alliance wants greater protection for victims of cyber-bullying after the clip remained on Instragram for nearly 22 hours.
Luke Roberts told IBTimes UK: "It is important that young people, the media industry, government and parents work together to make young people feel protected when online.
"During Anti-Bullying Week we deliberately focused on cyber-bullying and the impact of technology on their behaviour.
"It is important to remind young people that the information that they put online is permanent and difficult to take down.
"Young people don't seem to comprehend that what you do at 14 might affect you when you are 19 looking for a job."
Kidscape director of services Peter Bradley called the video "shameless" and inisisted that young people needed to together to stop "these terrible crimes".
"These actions illustrate the thousands of young people who have taken a part in an attack on an innocent young woman and the images posted on the internet," he said.
"The appalling footage should have been taken down from Instagram immediately. However, due to the website's moderators being too slow to respond, the horrific footage went viral immediately. As it was also liked by thousands of people over a period of hours, it spread across the globe like wildfire.
"The tens of thousands of young people who watched and 'liked' the video were wrong. The thousands of people who followed the attacker on Twitter were irresponsible and wrong."
In the 90-second clip the perpetrator, Sharkeisha, is captured punching another girl in the face and kicking her in the chest after she fell to the ground.
Instagram's terms and conditions specify that "violent, nude, partially nude, discriminatory, unlawful, infringing, hateful, pornographic or sexually suggestive photos" are banned from the site.
While it has not commented on the video, it said that it "encouraged people who come across content that makes them uncomfortable to report it to us using the built-in reporting tools next to every photo or video on Instagram, so we can review it and then take action".
A number of Twitter users have claimed that the filmed assailant was arrested by police and subsequently released on $500 bond.