WEATHERFORD, Texas (AP) — Investigators say one adult has been critically injured and several students were slightly hurt when a school bus was hit head-on by a car in North Texas.

The Department of Public Safety says the Bridgeport Independent School District bus was struck Saturday night on Farm-to-Market Road Road 51 near Weatherford. That's 20 miles (32.19 kilometers) west of Fort Worth.

Sgt. Ricky Hunter on Sunday said authorities are trying to determine why the southbound car hit the bus, which ended up on its side.

Hunter says a woman in the car was critically injured and transported to a hospital. The male driver was also hurt. Hunter had no additional details.

Five girls on the bus and that driver suffered minor injuries.

A message left with Bridgeport ISD wasn't immediately returned Sunday.