Updated 12:20 p.m.: The attacker in this case reportedly wielded two knives when he injured 19 students and 1 security guard before being tackled by an assistant principal. Those injured were either slashed or stabbed, and 4 are currently in critical condition. The security guard reportedly suffered a stomach wound. Two of the students in critical condition reportedly suffered chest wounds. Other students were treated and released for superficial wounds.

Updated 9:15 a.m.: Seven teenagers and one adult were admitted to Forbes Regional Hospital with significant injuries. Chris Kauffman, the hospital's director of trauma, told reporters that three people’s injuries warranted surgery. The injured ranged in age from 15 to 60.

Twenty people at a Pennsylvania high school were injured Wednesday morning – four seriously – when a teen attacked fellow students with a knife.

Several people were reported stabbed shortly before classes commenced at Franklin Regional High School in Murrysville, Pa. The first 9-1-1 call was placed at 7:13 am. According to Westmoreland County emergency management spokesman Dan Stevens, it doesn’t appear as if anyone suffered life-threatening injuries, and not everyone was cut by the attacker. Some suffered scrapes and cuts during the panic that ensued at the school, Stevens said.

The suspect, a male student, has been taken into custody. Officials have not said what sort of knife he used or what his motive was.

We will update this story as more information becomes available.