13-year-old girl badly injured in school fight with best friend

A 14-year-old girl was caught on camera viciously attacking a fellow student, at one point even pulling a knife from her trousers to stab her assailant.

Focus On Media, a news agency with an office in Rio de Janeiro, was credited for obtaining the footage, and the short video clip was shared on Daily Mail.

Please note, the video shared on the outlet's website contains images that some viewers might find upsetting.

Two teenage girls wearing matching activewear clothing can be seen brawling and grabbing each other by the hair while eyewitnesses look on.

At approximately 15 seconds in, one of the girls pull a night from her trousers and stabs her victim repeatedly in the back, shoulders, and arms.

The teenagers tumble to the ground, and a woman wearing a yellow top walks over and pulls the injured girl up by her hair.

When the two girls regain their balance, still holding each other by the hair, the assailant stabs the girl again, repeatedly, but this time in her chest and face

Eventually, the woman with the yellow top steps in again, and the two girls step away from each other before the footage ends abruptly.

The details surrounding the case are still vague. The fight could allegedly be traced back to a video shared on social media which one of the girls had a problem with.

According to Daily Mail, the incident reportedly took place outside a school in Belem, Brazil. Authorities are investigating, but the facts of the case could not be confirmed at this time.

The video has since gone viral, and a Twitter user known as Natalie Rose said mothers who allow incidents such as these make her sick.

'How [are] you giving your child a knife to hurt another child?' she asked. Whether the woman in the yellow top was the girl's mother is yet to be confirmed.

The story is still developing. Please follow our official Twitter account, AmoMama USA, for more updates.