Update at 11:10am --
According to NBC News, authorities say the suspect is a 16-year-old student who was flashing two knives.
The teenager, who hasn't been identified, went through the classrooms and a first-floor hallway in the high school located outside Pittsburgh.
At least 19 students and a security guard were hurt.
A principal tackled the stabber, and the security guard suffered a stomach wound.
Update at 9:10am --
At least two students are in surgery, and others were undergoing CT Scans and X-Rays and could require surgery later.
NBC News is also reporting the suspect (who is in custody) is a sophomore.
Still no motive is known.
Update at 8:40am --
According to NBC News, seven teenagers and an adult were all taken to Forbes Regional Hospital.
Dr. Chris Kauffman says the seven had stab wounds to the chest, back and abdomen.
He characterized some of the injuries as life-threatening and said students were in the operating room.
"These are quite serious injuries," said Kauffman. "These are not superficial in nature."
NBC News --
As many as 20 students were hurt when a classmate went on a stabbing rampage through the classrooms and hallways of a high school outside Pittsburgh on Wednesday morning.
According to authorities, the student suspect is in custody and is being questioned by police.
Dan Stevens, a Westmoreland County Emergency Management spokesman, says that the motive is unclear.
Victims as young as 15 were taken to four Pittsburgh-area hospitals.
Two were in the operating room and a third was on the way.
That's what Doctor Chris Kaufmann, a hospital trauma director, told CNN.
One hospital reported it had patients as old as 60 years of age.
The stabbings were reported at Franklin Regional High School, in the suburb of Murrysville.
Ambulances swarmed the parking lot.
Stevens said that the first call for help from the school came at 7:30am, shortly after the school opened its doors for the day.
The situation was under control by around 7:40am.
The school district website said that high school students and middle school students nearby were "secure," and that the elementary school had been canceled for the day.
They cited "a critical incident" at the high school.
Streets around the school were sealed off.
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