A student was taken to hospital in unstable condition from St. John's High School in Winnipeg after being stabbed Thursday afternoon.
Police say the teenage boy remains in critical condition but has stabilized in hospital. He received stab wounds to the upper body.
The teenage boy was in either Grade 10 or 11, Winnipeg School Division chair Sherri Rollins said.
Winnipeg police described it as a "serious assault" and taped off a portion of Machray Avenue near the school. The street has since reopened.
Investigators are interviewing a number of people about the incident and are also investigating a second address on College Avenue, police said.
Emergency crews were called to the high school at 1:47 p.m., police said.
St. John's was under a hold and secure protocol earlier Thursday, meaning external doors were locked but students could move around within the school.
The school has since reopened.
A spokesperson for the Winnipeg School Division said a letter was sent home to parents Thursday about the incident and counselling services will be provided.