Police say they responded to Hillcrest High School on Dauphin Road near the Ottawa Hospital General Campus at approximately 9:10 a.m.
A boy in his late teens was assaulted with an edged weapon, Ottawa paramedics say. He suffered serious injuries and was transported to hospital in stable condition.
Police say a second person is in serious but stable condition. Paramedics say they attended a local hospital on their own. Its unclear if they attended the school.
In an update, police said one youth suspect was arrested when officers arrived and another three were taken into custody during a search of the school.
No charges have been announced. The suspects cannot be identified under the Youth Criminal Justice Act.
The Ottawa Carleton District School Board (OCDSB) says there was an altercation inside the school and confirmed the boy was a student.
The school staff immediately contacted emergency services and police and paramedics responded. The school administration team activated a lockdown school procedure to ensure students and staff were safe, a spokesperson said in an email.
The lockdown was lifted at around 1 p.m. and Hillcrest was placed into a secure school mode.
A Grade 9 student told CTV News she arrived just after 9 a.m. when classes began to find the school in lockdown.
Im terrified, scared, and I feel really bad for the people who did get hurt and the people who are stuck inside, she said.
Im surprised its happening here and this is a scary experience for some people and probably traumatizing.
Another Grade 11 student said he saw paramedics taking a person out of the building.
I saw somebody come on a stretcher and there was police and ambulance and paramedics escorting him out, he said.
I hope that guy is okay.
The investigation is ongoing.
Ottawa Police are asking anyone who witnessed the incident or has information to contact the East Criminal Investigation Section at 613-236-1222, extension 3566.
Anonymous tips can be submitted to Crime Stoppers at 1-800-222-8477 or online at crimestoppers.ca.
