According to the school superintendent in the small town of Fort Gibson, south-east of Tulsa, the shootings happened just before 8am, as pupils were waiting to enter for the first classes of the day. "Another student just walked up and opened fire on them," said Steve Wilmoth, who added that it seemed to be "a random thing".
Muskogee County Sheriff's Deputy Terry Cragg said the suspect, being detained in the county jail, had not said anything about the shooting or his motive for allegedly carrying out the attack. "We do not have anything from him at this time," he said. "The suspect still had the weapon in his hand when police arrived. The weapon at that point was emptied."
Two boys were taken to a local hospital and a 12-year-old girl and 13- year-old boy were airlifted to Tulsa. The girl had a bullet wound to her cheek. A spokeswoman for the Fort Gibson medical centre said one of the victims, a boy of 13, was shot in both arms.
Another pupil, Justine Hurst, 13, said they they rushed screaming and crying to the school cafeteria, leaving their backpacks strewn around the entrance.
She said she knew the alleged gunman. "He seemed like a really nice person," she said. "He had a lot of friends."
The view was echoed by other Fort Gibson residents. One parent said: "He's not a problem child. He's a very good kid, a very friendly, polite child."
President Bill Clinton said: "Our prayers are with each of the children and their families and the entire Fort Gibson community. Right now there are no fatalities, only people who are wounded, and we hope and pray it will stay that way."
The Oklahoma Governor, Frank Keating, called on Oklahomans to teach their children the value of human life. "What we do know is one child injured other children and that act of that one child is evil and unforgivable." he said. "That simply should not be permitted in civilised society."
Past school shootings, including last year's mass shooting at Columbine High School. near Denver, Colorado, in which 15 people including the two gunmen died, have mostly involved loners who were shunned by other pupils. Fort Gibson has about 3,500 residents and is far removed from the endemic violence that plagues America's big cities. Strangely, however, several of the school shootings have taken place in similar, relatively affluent, communities.
Yesterday's shooting was the third such attack since the Columbine massacre, and the second in which a pupil was the alleged gunman.
A 15-year-old was charged with wounding six of his fellow pupils at a high school in the town of Coyers, Georgia, in May, and five people were wounded at a Jewish kindergarten north of Los Angeles in August. The presumed gunman, a 37-year-old man belonging to a white supremacist group, was also charged with killing a postman.
All previous school shootings have been seized on by supporters of gun control, to reinforce their argument for stricter laws on weapons possession. Attempts to pass legislation, however, have been repeatedly thwarted by the power of the National Rifle Association, which makes big contributions to congressmen's campaign funds, and by the fear of crime, which encourages people to keep guns for their own protection.