A high-school student in the US state of Pennsylvania has stabbed 19 pupils and a security guard in classrooms and hallways.
Police said a male suspect, aged 16, was taken into custody at Franklin Regional High School in Murrysville, a suburb of Pittsburgh.
The wounded, some with serious stab wounds to the torso, were as young as 14. Several were in surgery in hospital and two were in critical condition.
But the BBC reports all are expected to survive.
The attacks began around 7:13 a.m. EDT on Wednesday.
The school was evacuated quickly after the fire alarm was sounded, said Murrysville police chief Tom Seefeld.
"What we teach is, the first thing you want the students to do is run," Seefeld said. "The fire alarm being pulled probably assisted with evacuating the school."
The school will be closed for several days.