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Murrysville, Pennsylvania (CNN) - A teenage boy wielding two knives went on a stabbing rampage at his high school in Murrysville, Pennsylvania, early Wednesday, before being tackled by a principal, authorities said.
At least 20 people at Franklin Regional Senior High School, about 20 miles east of Pittsburgh, were injured, according to hospital officials, and the accused attacker - a 16-year-old sophomore - is in custody, Police Chief Thomas Seefeld said.
The carnage began shortly before the start of classes, with the accused allegedly going from classroom to classroom.