A 14-year-old schoolgirl arrested after a teacher was stabbed in the neck at a school in Manchester yesterday has been detained under the Mental Health Act. Police confirmed the girl had been arrested on suspicion of assault after officers were called to reports of a stabbing at the Co-op Academy in Blackley on Tuesday morning. The 'serious incident' saw the school go into lockdown after a teacher was stabbed in the neck as he heroically shielded pupils from a girl allegedly attacking students at the school with a knife. A girl and a boy, both 14, and a 27-year-old male staff member were taken to hospital after the incident. Police confirmed this evening that all three have since been released after being assessed. Staff at the school on Plant Hill Road were quick to detain a girl after the incident to ensure no further harm came to students or staff before officers arrived shortly afterwards, the force added.City of Manchester North Chief Inspector Jon Shilvock said: 'Our thoughts are with those that were injured and were caught up in the incident.'Whilst the physical injuries were not believed to be serious, we know the impact to those that were involved or were witnesses to this will be significant, and we want to reassure our community we are taking this very seriously.'Chief Inspector Shilvock added: 'As our investigation progresses, we are aware that names relating to the incident are being circulated on social media, which are unhelpful for the investigation. Large crowds of pupils and parents gathered at the scene after the stabbing yesterday at a school in Manchester Co-op Academy Manchester is a non-selective, mixed secondary school on Plant Hill Road in the suburban area of Blackley (file image)'This is also causing concern with the victims and those that have been impacted, therefore we would stress that people do not speculate regarding this incident.'Officers will remain in and around the area to provide support to ensure staff, students and the wider community feel safe.'If you have any concerns, please speak to our officers who are there to support you.'Witnesses identified the adult victim as a science teacher, known as Mr Abdullah, who was stabbed as he tried to wrestle a knife from a student. Five teachers were said to have held the classroom door shut with the armed schoolgirl trapped inside. 'She tried to get outside the classroom to attack other kids but other teachers held the door closed on her,' a witness said. One girl reportedly screamed 'I've been stabbed' as she fled from the attacker. Emergency service vehicles were pictured outside the gates and on the school grounds on Tuesday. Police and ambulance vehicles were pictured outside the gates and on the school groundsA helicopter was also seen above the building as large crowds of pupils and parents gathered at the scene. In a message to parents and carers, the school's headteacher, Phill Quirk, confirmed the academy would be shut for the rest of the day. He said: 'You will be aware that there has been an incident at Co-op Academy Manchester this morning. 'We can confirm that everyone is safe and the incident has been contained. 'However we have made the decision to close the school for the remainder of the day. We are speaking with parents and carers to obtain permission for children to leave. 'If we haven't yet spoken with you, please contact your child through their mobile phone or send an Arbor message. 'Once a member of staff has seen and verified this permission, students will be allowed to leave the site.'Co-op Academy Manchester is a non-selective, mixed secondary school on Plant Hill Road in the suburban area of Blackley. City of Manchester North Chief Inspector Jon Shilvock said: 'As our investigation progresses, we are aware that names relating to the incident are being circulated on social media, which are unhelpful for the investigation'Around 1,650 pupils attend the academy and it was rated Good in its most recent Ofsted inspection. The school 'chose' to go into lockdown as the stabbing incident unfolded this morning, it is understood.Heavy traffic has been reported outside the building with students waiting to be collected.Parents and pupils voiced their concern following the attack.One girl, who was standing next to her mother outside the building, told the Daily Mail: 'It was terrifying. The teacher tried to get the knife off her but ended up being stabbed in the neck.'She tried to get outside the classroom to attack other kids but other teachers held the door closed on her.'She eventually dropped the knife and was arrested. I saw her being brought out in handcuffs.'A father-of-two, who spoke as he picked up his Year 9 son from school, said: 'My son said the teacher was stabbed as he tried to get the knife off the girl.'He was trying to grab her to get her away from the other children. But he was stabbed. Another girl was stabbed in the arm.'All the children were very scared. He said the girl had gone crazy.'A mother, whose son was already on his way home when she received the news, said on social media: 'This is all so scary. Parents found nothing out from school, it was all from Facebook. My child should be enjoying the last few days in school and not worrying and being in lockdown.'Another parent said she only received confirmation of the incident after arriving on site to collect her daughter.Malik Attiqe, 41, whose 14-year-old son is a pupil, said: 'It's very scary. My son said the science teacher was stabbed in the neck at the school. She also attacked other pupils.'The Government needs to do more to stop knife crime.'It's terrifying this could happen in a school and this girl brought a knife into a classroom.'Consuela Lugia, 35, whose son is a pupil at the school, added: 'It's terrifying.'I was really worried for my son when I heard about the stabbing.'Greater Manchester Mayor Andy Burnham issued a statement in the aftermath of the attack.He said on Tuesday: 'I will be in touch with GMP throughout the day. As I understand it, it's not an intruder coming into the school, it would appear to be an issue within the school.'It seems like a very serious issue, alarming for all, especially pupils parents. It seems right now that the right actions have been taken and we'll work with the school to get to the bottom of things.'I continue to perform my mayoral duties. I separate them from the election campaign. I am still receiving reports of incidents I need to deal with.'Co-op Academy Manchester said the incident had occurred 'shortly after the start of the school day'.In a statement, the Co-op Academies Trust told the Daily Mail: 'The school was immediately placed into lockdown, and staff acted bravely to quickly detain a student before emergency services arrived.'Greater Manchester Police arrested the student, who remains in custody. Police have confirmed this was an isolated incident with no wider threat to the public.'Three people, two pupils and a member of staff sustained injuries. They were taken to hospital as a precautionary measure, where they are in a stable condition with injuries not believed to be serious.'The trust said it was 'incredibly proud' of the 'swift actions' of staff and 'mature response' of pupils.Co-op Academy Manchester will reopen as normal tomorrow with 'full emotional support' in place for pupils and local officers maintaining a 'reassuring presence' in the area.The trust added its policies outline 'strict screening and search powers in line with Department for Education guidance'.But it concluded: 'Weapons can unfortunately be small and easily concealed without prior indicators. 'We had no reason to conduct a search on any student this morning.'