A 6-year-old Springfield boy was run over and killed yesterday afternoon by a Fairfax County school bus from which he had just alighted.

County police and school officials called the death of Michael Duhrkoop, a kindergarten pupil at Lynbrook Elementary School, the first fatal accident in the history of the county school system, which operates about 700 buses to transport about 83,000 children daily.

The accident occurred shortly after 4 p.m. after about 40 children from Lynbrook got off their school bus on Cork Glen Way in Springfield.

After the bus had emptied, its driver, a 41-year-old woman who has driven school buses for the county for two years, started the vehicle and made a left turn, police said, then stopped when she heard a group of children shouting.

"She stopped, looked around, then pulled forward again," said Warren Carmichael, county police spokesman. "She apparently concluded nothing was amiss, and she may have been under the impression the kids were just making noise."

After proceeding about one bus-length, the driver felt a thump under the left rear wheel, stopped, got out, and found the child crushed, according to police. Investigators said Michael apparently had been standing in a spot near the bus' left front fender where he was not visible to the driver. Michael, who lived at 7614 Cork Glen Way, was pronounced dead of internal injuries at Mount Vernon Hospital.

Investigation of the accident is continuing.