A children's charity has criticised one of the world's most-watched websites for hosting a video of two schoolgirls from Cardiff having a vicious fight.
The video shows the girls surrounded by a crowd of children
YouTube allows users to post content directly, and it includes the film among many so-called "bitch fights".
Anti-bullying charity Kidscape called for the video to be taken down.
One of the girls, from Llanishen High School, ends up with blood over her face. Cardiff Council said it was very concerned about the footage.
An education spokeswoman confirmed there was an out-of-school incident earlier this summer.
The fight, filmed on a mobile phone earlier this summer, begins with the taller of the two talking to the other girl, as they are surrounded by other children.
The grainy footage, which is less than a minute long, shows them wrestling with each other for some moments before the smaller girl kicks upwards twice and repeatedly hits the taller girl in the face.
The bigger girl is pushed to the floor and a number of other youngsters join in and start kicking and hitting her. She ends with blood on her face and is led away by other girls.
Michele Elliott, director of the anti-bullying charity Kidscape called for those involved, including the onlookers, to be punished by the school.
Harsh blows are given, with one girl ending bleeding from the face
"In the office we watched it and stood there with our mouths open," she said.
"We couldn't believe it was happening, and being filmed and people were not intervening.
"Not a single person said, enough is enough. It was like it was planned and 'we're all going to watch'.
"I wanted to leap into the website and protect them."
Ms Elliott said if she was head teacher at the school, she would hand out "harsh suspensions at the very least" to the people involved.
She said she would like the video removed but added: "The servers [which host websites] always say they can't monitor everything because there are millions and millions of videos."
A search for "bitch fight" on YouTube returns more than 1,000 hits.
No-one from YouTube was available for comment.
Its website states: "YouTube doesn't allow videos with nudity, graphic violence or hate."
It also asks users to flag unsuitable videos as "inappropriate" and report them to YouTube.
A spokeswoman for Cardiff council's education department said two pupils from Llanishen High were involved in a "distressing altercation" out of hours and not on school property a few months ago.
Police dealt with the incident and it was referred to the school.
She added: "We are very concerned at the footage displayed on the website and the nature of the content on these sites is one of the reasons why they are blocked by the council's internet content management system."