Six Oakton High School students were injured -- one critically -- after a BMW sedan with four teenagers inside careened out of control, jumped a curb and struck three others walking home from school on the sidewalk.

The three pedestrians were most seriously hurt. A 13-year-old freshman girl was unconscious and in critical condition last night at Inova Fairfax Hospital, school officials said. One other student struck by the car was in fair condition at the same hospital, and all others injured in the accident either had been or were to be released from hospitals by late last night.

"It's obviously a horrible situation," said Oakton Principal Charles Ostlund.

Fairfax County police said the 2001 silver BMW was heading south on Blake Lane in Oakton about 2:20 p.m., when the 17-year-old driver lost control about a quarter-mile from the school and headed toward the curb. Officer Jacqi Smith said the BMW bounced back into traffic and struck a green Toyota van driven by Seung Yu, 38, of Fairfax, who was driving her child home from the school.

The BMW then jumped the curb in front of a house in the 9800 block of Blake Lane, struck the three students and smashed into a wooden privacy fence and tree before coming to a stop near Bel Glade Street.

Police investigators do not know whether the BMW was speeding or what else might have caused it to sideswipe the van and jump the curb. No charges were filed yesterday, and police said the investigation was continuing.

Ostlund said he spoke to two of the students who were hit by the car and to the driver and some of the passengers in the BMW. "The sense I get is that this is truly an accident," he said. "Talking to the driver of the car, I don't think he was ever aware that he had struck anyone. . . . He had very little recollection of anything."

The three pedestrians barely had time to react as they walked along the busy street, Ostlund said. He said one of the students told him that all three had their backs to traffic and that "they heard a loud noise, and as he turned, he saw the car coming, but there was a fence and just no place to go."

Describing the third student hit by the car, Ostlund said: "Her heart jumped. It happened so fast. There was nothing she could do. She was very frightened and shocked and paralyzed."

Those two students were sitting up in the hospital, wearing neck braces, with bruises and cuts but no apparent serious injuries, Ostlund said. The principal said he would address the school Monday to tell them how the students were doing and "to once again reinforce the importance of using extra care and caution."

Neither police nor school officials identified any of the students. Amar Desai, a friend of the driver, said the 17-year-old got the BMW as a gift from his parents about two months ago. The driver called Desai from the ambulance to say he had been in an accident, that he had tried to avoid a van driving too closely to the BMW and that he had driven onto the sidewalk.

"He's really scared right now," Desai said.

One of the passengers in the BMW, who declined to give his name, said he was in the back seat. "I remember a van and we switched lanes to the right, and then we hit the curb," he said. "I don't remember anything else. I blacked out for a while."

That passenger was treated for bruised ribs at Inova Fairfax Hospital and released. Another passenger was treated at Inova Fair Oaks Hospital and released, and a 15-year-old passenger was still being evaluated there. The fourth person in the car was not injured, police said.

Staff writers Jacqueline L. Salmon, Jamie Stockwell and Josh White contributed to this report.