Three students were injured in a stabbing at Carrick High School on Wednesday morning, authorities reported. Pittsburgh police, firefighters and EMS crews responded to what officials described as a “critical incident,” according to Pittsburgh Public Safety.

According to a report by CBS News, a spokesperson for Pittsburgh Public Schools released a statement detailing the incident, saying a student used a “small knife” to injure three other students.

As of 9:25 am, all victims were receiving medical care, according to Pittsburgh Public Safety. Two students were taken to the hospital with abdominal stab wounds. One remains in critical condition and the other is listed as stable.

Officials said the student accused in the attack is in custody. The suspect suffered a hand laceration, received on-scene treatment from medics and was then handed over to police, according to a report by CBS News.