Dee Duren, NewsOn6.com

SAND SPRINGS, Oklahoma -- A Sands Springs father ran over one of his children while off-roading Friday afternoon. The 8-year-old boy is in serious condition at a Tulsa hospital.

It happened on private property near West 46th Street South and 166th West Avenue at 4:35 p.m.

Michael W. Eckfeldt, 34, was driving a Jeep Wrangler on a large mound of dirt in his back yard with three children in the vehicle, according to the Oklahoma Highway Patrol.

As the jeep was going up the mound, Eckfeldt's son Andrew jumped from the rear of the jeep to the ground, fearing that the vehicle would roll over backwards. His father engaged the clutch, allowing the vehicle to roll back down the incline, and ran over his son.

The boy has internal injuries, according to Trooper Shawn Vann.

The driver's 9-year-old son and 10-year-old daughter, who were also in the jeep, were uninjured. The vehicle was only equipped with seat belts in the front seat, according to the trooper's report.

The driver was in apparently normal condition at the time of the incident, the report states. The cause of the incident is under investigation.