Witnesses describe students running silently for their lives as a gunman opened fire in a Kentucky high school.

Sixteen-year-old Alexandria Caporali says "no one screamed" during the Tuesday morning shooting at Marshall County High School in rural western Kentucky.

Some of the children ran into classrooms to hide from the boy with the gun. Some ran out of the building, into the fields, across the streets, through the doors of nearby businesses.

Parents desperately searched for their teenagers; business owners pulled fleeing youths to safety; a state trooper rushed to the school, terrified he would find his own daughter among the dead.

A 15-year-old male student has been arrested in the shooting, which killed two classmates. A dozen others suffered gunshot wounds, and five were injured in the scramble to get away.