Videos showing young people being bullied should not be shared online because victims are being forced to relive their suffering, a children's charity has warned.
Sharing the footage in a bid to raise awareness ends up having a negative effect on young people - both those being bullied and others who see the videos, the NSPCC said.
The charity is calling on social media firms to block such videos and urging members of the public to report recordings rather than sharing them.
One clip showing a 13-year-old girl being dragged along the ground and punched in the head while people watched was viewed more than 600,000 times, the charity said as it launched its #BlockTheBullying campaign alongside The Sun.
In another incident a father told the newspaper he discovered his 12-year-old son had been beaten and pinned to the floor when a video emerged on social media app Snapchat.
With videos being filmed and shared on the internet, young people now have no escape from bullying, the charity's chief executive Peter Wanless said.
He said: "Enabling videos of abuse to be shared and circulated may seem like a good way to raise awareness but it can have a very damaging effect, forcing the young person to relive their humiliating and terrifying experience repeatedly.
"Years ago a child could escape the bullying when they left the playground and get some respite in the safety of their home, now the 24/7 nature of the internet means that a child can be targeted around the clock."
Keith Poole, The Sun's digital editor, said he is shocked at the number of videos they have been sent showing schoolchildren being attacked, "often with appalling viciousness".
He said: "We are therefore pleased to be working with the NSPCC to tell readers what to do if they come across these videos online and how parents should help their children if they are subject to such bullying.
"We are also keen to inform our younger readers and their parents of the heartbreaking consequences of being involved in this new form of cyber-bullying.
"The Sun is happy to be leading the way by committing not to run such videos in the future and we hope others, including social media companies, follow our lead and remove these videos as soon as they are flagged."
:: Parents worried about online safety can visit the NSPCC website or call the helpline on 0808 800 5002. Children can call Childline at any time on 0800 1111 or visit www.childline.org.uk.