A Smithfield mother was killed Thursday morning in a head-on collision with a tractor-trailer hauling livestock on Route 258 between Smithfield and Windsor.

Two children — a 6-year-old girl and a 3-year-old boy — who also were in the car were taken to the hospital with life-threatening injuries, according to a state police report.

Amy C. Pippin, 26, of Carroll Bridge Road in Smithfield, was driving a 1986 Ford Thunderbird southbound on Route 258 at about 8:30 a.m., when she attempted to pass a vehicle in front of her and was hit head-on by a northbound tractor-trailer, according to state police.

Pippin died at the scene. The children were taken by ambulance to Sentara Obici Hospital, but they were later transferred by helicopter to Sentara Norfolk General Hospital with life-threatening injuries. Hospital officials said Thursday evening that the children had been moved, probably to CHKD.

The driver of the tractor-trailer, whom police did not identify, was taken to Obici with injuries that were not thought to be life-threatening.

All of the people involved in the accident were wearing seat belts, police said.

The tractor-trailer was carrying a load of livestock when the collision occurred, and several of the animals died in the collision, police said.