A rail car filled with liquefied natural gas has exploded after a freight train derailed in the middle of a small town in northern Italy.

The blast set off an inferno, killing at least 13 people and injuring 50 others. Officials say the number of victims might rise as rescue teams search through the rubble.

The blast occurred in the town of Viareggio early in the morning when a train carrying gas-filled tank cars was moving close to the station. Some 300 firefighters were digging through the rubble of collapsed or burnt homes looking for casualties.

The cause of the accident is still under investigation. The 14-car train carrying the liquefied gas was travelling from the northern city of La Spezia to Pisa.