The incident happened in New Earswick yesterday afternoon and involved students from nearby Joseph Rowntree School.
North Yorkshire Police said the force was contacted at about 3.30pm yesterday with reports of violence taking place near to the New Earswick shops on Haxby Road, York.
“Eye-witnesses reported that a group of secondary school age children from Joseph Rowntree School were involved in a physical altercation,” said a spokesperson. “A woman who became involved in the incident was also physically assaulted.
“Officers are engaging with the school and an investigation has been launched to determine the circumstances around the incident.
“Police are requesting that those who captured mobile phone footage of the assault give consideration to those who may have been targeted and not share it on social media platforms.
“Instead, anyone who did capture footage, or has any information which would assist the investigation, is asked to contact North Yorkshire Police on 101 quoting reference 12230045667. Crimestoppers can be contacted anonymously on 0800 555 111.
Mr Hewitt said in his email to parents and carers that he wanted to tell them about an incident that ‘happened after school and away from the premises, involving a group of our students as well as members of the local community.’
He said the school expected all of its students to behave well on the way to and from school, as well as in school.
“We have sanctioned individual students directly involved in the incident in line with our behaviour policy,” he said.
“We have also spoken to other students who were present at the incident to remind them about our core values and expectations of their behaviour when they are travelling to and from school.
“We will be contacting parents/carers of these students later today to reinforce our expectations of their children’s conduct.
“The vast majority of our students always behave themselves well in school and in the local community and I wanted to reassure you that we will not accept behaviour of this kind from any of our students.
“Whilst we fully appreciate how well the majority of our students uphold our core values and expectations, could we ask that you take some to discuss and reinforce these expectations with your children.”
The grandmother of a pupil at the school has told The Press that the girl and her pregnant mother had been attacked, and the mother had been for a scan today to check her unborn baby had not been harmed.
She said video footage showing the attack was ‘all over social media,’ adding: “It seems to be the norm now to pick on someone en masse and film it.”
She said her granddaughter had been collected from school by her family as a precaution because of an awareness that she was at risk, and a large number of pupils then descended on her home, outside which the incident took place.