Dozens of police officers were sent to a South Yorkshire secondary school after a large fight broke out between pupils.
Footage posted on social media showed officers trying to restrain youths amid a melee outside Fir Vale School in Sheffield.
The school was forced to close early on Tuesday but assured parents that all pupils were safe.
Paramedics treated two people at the scene for minor injuries. One is thought to have been a school staff member.
A witness claimed as many as 150 people, including parents, were involved in the disorder.
“All hell was breaking loose,” they told local newspaper The Star. “We saw two police riot vans and police dogs. We saw parents and pupils trying to climb over the fences.
“I’d say there were about 100 to 150 people rioting and there was chaos on both sides of the fence.”
A South Yorkshire Police spokeswoman said: “At around 12.55 this afternoon, police were called to Fir Vale School on Owler Lane, following reports of an altercation between a group of students.
“Officers were deployed and on arrival found that a large number of people had gathered at the gates.
“The crowds have now dispersed and officers remain in the area, liaising with the school.”
No arrests were made.
Officers have cordoned off the school and several police vans remained parked outside on Tuesday afternoon.
Videos of the disorder posted on Facebook have been viewed more than 50,000 times.
“Look at this, they’re attacking the police. What the f***,” a man is heard saying in one of the clips.
Passer-by Steve Harrison said he “counted 10 police cars, two of which were dog units, a police van and four ambulances” at the scene.
In a message on the school’s website, headteacher Simon Hawkins said: “An incident in school has meant we will be closing at 2pm. All pupils are safe. Any child who should not leave early will be supervised on site in our library.”
The school was praised for the behaviour of its pupils in its most recent Ofsted report, with inspectors noting in 2015: “They are proud to belong to the academy, and treat its facilities with respect.”
