At least 10 people were killed Wednesday when a bus carrying state prisoners skidded off an icy highway in Texas, slid down an embankment and collided with a passing train, a county sheriff said.

The overpass on an interstate highway was slick with ice Wednesday morning when the Texas Department of Criminal Justice bus left the roadway just west of Odessa, according to Ector County Sheriff Mark Donaldson.

The Texas Department of Criminal Justice said in a statement that eight prisoners and two corrections officers were killed. It said four prisoners and one corrections officer were injured.

Tiffany Harston, spokeswoman for Medical Center Hospital in Odessa, said four of the injured are in critical condition and one in serious condition.

Justice department spokesman Jason Clark said the bus was carrying 12 prisoners and three corrections officers to the Sanchez prison in El Paso.

The white bus came to rest on its side, crumpled with heavy damage to its top and undercarriage.

The Union Pacific freight train with four locomotives and 58 cars came to a stop soon after. None of the cars derailed, but two containers at the rear of the train were damaged when the bus struck them, said Mark Davis, a railroad spokesman.

The containers were carrying hundreds of parcels and packages, many of which were strewn along the tracks.

Two Union Pacific employees were not injured.