Multiple people were stabbed at a high school in the suburbs east of Pittsburgh, officials said.
Emergency management spokesman Dan Stevens said four students were believed to be seriously injured when a student with a knife stabbed or slashed others, injuring as many as 20.
Stevens said not all of the 20 injured were cut by the knife, though most were. Some suffered scrapes and cuts in the mayhem that ensued at Franklin Regional High School on Wednesday morning. Stevens says it doesn't appear any students suffered life-threatening injuries.
While Stevens said all the injured are between 14 and 17 years old, hospital officials told CBS Pittsburgh the patients they were taking in from the incident range from 15 to 60 years old.
Police say the 16-year-old male student suspect is in custody and is a sophomore at the high school.
He was transported from the Murrysville Police Department by police car, and reportedly taken to a local hospital for superficial wounds.
Jeff Dahlke, who works for the company that provides security for Franklin Regional High School, told CBS Pittsburgh that the suspect was armed with two knives.
"The alarm went off, and students started rushing outside, the security guard outside rushed in, and came upon his supervisor, and an assistant principal who had the suspect in custody on the ground and was trying to control him, and try to get the weapons away from him," Dahlke said.
The incident occurred around 7:13 a.m.
Three air medical helicopters have been dispatched to the scene as well as dozens of ambulances.
According to a witness, the stabbings happened in the science wing of the building.
Franklin Regional school district has canceled all elementary classes and say that high school and middle school students are secured.
The FBI is on scene at the high school shooting. Federal officials stress, however, that the stabbing remains a local investigation and that local police are in charge.