'Critical incident': Three students injured in stabbing at Carrick High School, Pittsburgh; suspect in custody

At least three students were injured in a stabbing at Carrick High School, Pittsburgh , on Wednesday morning, authorities reported.

Pittsburgh police , firefighters, and EMS responded to the school following what Pittsburgh Public Safety described as a "critical incident."

The school was placed on lockdown, and the student responsible has been taken into custody, officials confirmed. A spokesperson for Pittsburgh Public Schools stated that a student used a “small knife” to injure three fellow students.

Emergency responders quickly arrived at the scene, and medics issued a red tag, indicating that at least one of the injured students is likely in critical condition, according to the Pittsburgh police scanner.

"While details are developing, we have been advised that one student's injury may be more serious," a Pittsburgh Public School spokesperson was quoted as saying by CBS News.

All victims were receiving medical care as of 9.25 am (local time) on Wednesday. Pittsburgh Public Safety reported that two students were transported by EMS with stab wounds to the abdomen, with one listed in critical condition and the other stable.

The suspect sustained a hand laceration as well and was treated on-site by medics before being taken into police custody.

The motive behind the incident has not yet been determined.

"We are grateful for the swift action of school staff, School Police, and the City of Pittsburgh 's first responders. Additional information will be shared as it becomes available,” a spokesperson from the school said.