MEDFORD, Okla. (AP) -- Authorities say a train has slammed into a propane tanker truck in north-central Oklahoma, triggering a large explosion that killed two people and injured a third.

The Ponca City News reports that the tanker was filled with propane shortly before it was struck on U.S. 81, about a mile south of Medford.

It's not yet known whether the victims were in the truck or the train. Oklahoma Highway Patrol Lt. George Brown says the survivor was airlifted to a hospital.

Union Pacific spokeswoman Raquel Espinoza-Williams says the train had departed from Wichita, Kan., heading to Fort Worth, Texas. She says it was hauling flour, wheat and some flammable substances. None of the flammable substances leaked.

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