Ch Insp Jon Shilvock said: “Our investigation has continued at pace since yesterday morning, when we were first made aware of the incident.
“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.
“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.
“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.”
He added officers will remain in the area “to provide support to ensure staff, students and the wider community feel safe” and if anyone had concerns to speak to officers.
Co-op Academy, which reopened today, praised its staff and pupils.
“We are incredibly proud of the swift actions of our staff and the mature response of our pupils,” it said.