The bloody ambush happened at the lunch hour at the Westside Middle School in Jonesboro, a rural town in north-east Arkansas. Children and teachers began coming out of the school after a fire alarm had been set off.
Police last night said they had arrested the two boys, thought to be pupils at the school. It seemed the youths, heavily armed and in camouflage clothes, had ran out of a wood and ambushed the children and teachers as they came out of the school. A third suspect, also a boy, was believed to have set off the fire alarm.
Altogether, 15 people were shot. All of the pupils struck in the ambush were girls. There were unconfirmed reports that of the four who died, one may have been a teacher.
It was the third fatal rampage by students in an American school in just five months. Last December, a 14-year-old boy fired on a school prayer group in his school in Padukah, Kentucky, killing three people.
Jonesboro is in a poor cotton-growing region of Arkansas, about 90 minutes' drive northwest from Memphis, Tennessee.
There were scenes of chaos around the school yesterday afternoon as parents rushed to the scene to find out if their children were among the victims. American middle schools are attended by children aged 11 to 14.
No motive was given for the shooting. Police officials said a white van was found parked close to the school after the shooting with weapons stashed inside.
Bob Trout, editor of the local newspaper, expressed his shock last night. "I could think of a thousand places where I could think of something like this happening, before I would think of Jonesboro, Arkansas," he said.
Ralph Lee, Jonesboro's mayor, was equally dumbfounded: "I just can't believe it. This is something that happens somewhere's else, not your own home".