SMITHFIELD, N.C. (AP) _ A van plowed into a group of middle school students today, injuring seven children, when the van inexplicably shifted into reverse and tore through an area where parents were letting children off for class, officials said.

The accident occurred at 7:45 a.m. outside Smithfield Middle School. Medical personnel transported the injured children and the van driver to Johnston Memorial Hospital, said Tom Davis, deputy superintendent of schools.

Three of the injured students were later transferred by helicopter to UNC Hospitals in Chapel Hill, Davis said. He said the students' conditions would be released later.

The van suddenly shifted into reverse after the driver had dropped off two children in the driving circle outside the school, Davis said.

``Suddenly, unexpectedly and for no reason that we know of, it moved into reverse,'' he said.

The van jumped a curb, crossed a grassy area at a high rate of speed and struck the students, said Davis.

A crisis team of social workers, counselors and psychologists was dispatched to the school.