MURRYSVILLE, Pennnsylvania. (ABC News) - A 16-year-old suspect armed with two knives allegedly went on a mass stabbing spree today inside a Pennsylvania high school before he was tackled by an assistant principal, according to authorities.
"The juvenile went down a hallway and was flashing two knives around and injured the people," Thomas Seefeld, the police chief in Murrysville, Pa., told reporters this morning.
The motive for the rampage at Franklin Regional High School was under investigation. However, Seefeld said the outcome could have been a lot worse if immediate action had not been taken.
The name of the 16-year-old suspect has not been released by police, but a student at the school told ABC News the person believed to be the alleged stabber seemed like a "pretty normal kid."
At least 20 people were injured after the stabbings at the start of the school day, Westmoreland County emergency management spokesman Dan Stevens said. No fatalities were reported.
At least four people with injuries Stevens described as "serious" were flown to area hospitals for treatment. Others were not actually stabbed, he said, and some of their injuries were cuts and scrapes.
Among the victims of the stabbing was a security guard stabbed in the stomach, the police chief said.
Dr. Louis Alarcon, who is part of an operating team at the University of Pittsburgh Medical Center Children's Hospital, said one victim, a 17-year-old boy, had a stab wound to the chest that barely missed his aorta.
Alarcon said doctors were optimistic the teen will survive.
At Forbes Hospital, Dr. Mark Rubino said his team treated eight victims, three of whom he said had severe injuries.
"We were ready to handle what came in the door," Rubino said, adding that, at one point, 20 surgeons were in the emergency room.
Rubino said the injuries spanned from "relatively superficial wounds" to "severe injuries to abdominal injuries." He said almost all of the stab wounds appeared to follow a pattern and were inflicted on the victims' lower abdomens.
The breakdown of injured and whether they were students or staff was not immediately known, but Forbes and Allegheny General Hospital initially reported nine patients ranging in age from 15 to 60.
Alyssa Finch, who said she is a student at Franklin Regional High School, told ABC News a fellow student pulled the fire alarm during the stabbing "because he knew what was happening ... and he wanted the people to get out."
A statement posted on the Franklin Regional School District's website said classes were cancelled today and that parents of middle school and high school students should report to Heritage Elementary for reunification. Any student who drove to school would not be released until a parent came to pick them up, the statement added.
Pennsylvania Gov. Tom Corbett said in a statement that he was "shocked and saddened" by the incident.
"As a parent and grandparent, I can think of nothing more distressing than senseless violence against children. My heart and prayers go out to all the victims and their families," Corbett said. "I have directed the Pennsylvania State Police to assist local law enforcement in its investigation in any way possible. Other state resources will be made available to the community, if needed. I assure the citizens of Murrysville that they have the full support of my administration."