A male student is in hospital with serious injuries and another student is in custody following a stabbing inside a North York high school on Tuesday afternoon, Toronto police say.

At around 1:40 p.m., police were called to George S. Henry Academy, near Highway 401 and Don Mills Road, for reports of a stabbing.

“When our officers arrived on scene they found that both the victim and the suspect had fled the school and our officers began investigating and reviewing some video,” Duty Inspector Michael Williams said at the scene.

The school issued a lockdown in response to the police investigation.

After looking at surveillance video police confirmed that a stabbing had occurred in a hallway, Williams said.

Forty minutes after implementing the lockdown the school then transitioned into a hold and secure, prohibiting anyone from leaving or entering the school.

“Why we still have the students on scene is our officers needed to secure the area and ensure that we could collect all the evidence properly and then transition to relieving the students from school safely,” Williams said.

Police were then alerted about a male student from the school who brought himself to a local hospital with injuries.

Williams said the victim’s injuries were assessed and he was transferred to a trauma centre in serious condition.

It is believed that the victim was stabbed in his abdomen.

Williams said both the victim and suspect attend the school and appear to know each other.

“It does appear that there was some kind of altercation, and again that's forming part of our investigation and figuring out exactly what took place and why and who these people are,” he said.

The suspect was seen fleeing northbound from the school and was wearing a grey hoodie and blue jeans following the stabbing.

At around 5:45 p.m., Toronto police said the suspect had been located and arrested.

Officers remain at the school and in the area investigating.

“So if any students…know anything about what happened or if anybody was in this area and saw a person dressed like that leaving this area, if you could please contact members of 33 division. We would very much appreciate it,” Williams said.

TDSB spokesperson Shari Schwartz-Maltz said the students and staff appeared to be very calm throughout the incident.

“You know, the kids go through a lot of lockdown drills, a lot of hold and secure lockdown drills, so even though we're at the beginning of school, you know they're in high school so they’re pretty used to going through this, and there is a sense of calm,” she said at the scene.

The hold and secure lifted around 4 p.m. and students were sent home.

Schwartz-Maltz said counsellors will be at the school on Wednesday for any students or staff who want to talk to them.