A train crash in the United States has left at least five people dead and around 50 injured, some critically.

At least seven carriages came off the tracks in Philadelphia – a witness said one had been bent into an L-shape.

The Amtrak train had been travelling from Washington heading for New York when it came off the rails in the of Port Richmond district.

Emergency services used ladders to straddle the wreckage and torches to search for survivors in the dark.

“I’ve been down on the tracks on the scene and with my staff. It is an absolute disastrous mess. Never seen anything like this in my life and most personnel would say that as well,” said the Mayor of Philadelphia, Michael Nutter.

The authorities said 238 passengers and five crew members were on board the train.

Dozens of people were taken to hospital. Survivors described scenes of panic and chaos as the train derailed.

“We could feel it off the tracks and we just rolled and rolled. The next thing I knew is that we