An Amtrak train carrying 238 passengers and five crew members has derailed and crashed in Philadelphia.

Philadelphia Mayor Michael Nutter said that at least five people were killed and 50 were injured. 

Train 188 was traveling from Washington, D.C., to New York City when the front of the train began to shake as it was going into a turn, Megyn Kelly reported.

The Associated Press reported: 

An Associated Press manager, Paul Cheung, was on the train and said he was watching Netflix when "the train started to decelerate, like someone had slammed the brake."

"Then suddenly you could see everything starting to shake," he said. "You could see people's stuff flying over me."

Cheung said another passenger urged him to escape from the back of his car, which he did. He said he saw passengers trying to escape through the windows of cars tipped on their side.

"The front of the train is really mangled," he said. "It's a complete wreck. The whole thing is like a pile of metal."

The cause of the derailment was unknown, but Amtrak said it was investigating. The area where the derailment occurred is known as Frankford Junction and has a big curve.

UPDATE 10:37p ET: Megyn Kelly reported that at least 50 people have been injured in the Amtrak crash. 

She said that police officers and firefighters are helping injured people into ambulances. 

The cause of the crash is unknown at this time. 

UPDATE 11:09p ET: Megyn Kelly reported that the National Transportation Safety Board is heading to the scene of the train accident.

Philadelphia Fire Commissioner Derrick Sawyer told that 10 of the train's cars derailed.

UPDATE 11:23p ET: Megyn Kelly spoke with a passenger who was on the train at the time of the accident.

Beth Davidz told Kelly that she was finishing up a phone conversation when she suddenly felt the train car shift to the right and tumble over. 

Davidz said that passengers were screaming and panicking trying to escape from the horrific accident. 

Watch the video below to hear more.

UPDATE 11:34p ET: Megyn Kelly reported that about 59 people are being treated for injuries at hospitals in the area.

She said that some residents in the area have reportedly showed up to the accident scene to give emergency responders bottled water. 

UPDATE 11:41p ET: Philadelphia Mayor Michael Nutter said that at least five people were killed and 50 were injured when a northbound Amtrak train derailed Tuesday night in Port Richmond. 

He said that this is a "mass casualty" situation and that more than 120 firefighters and emergency personnel have responded to the scene. 

"The trains' seven cars, including the engine, are in various stages of disarray - turned over, upside down, on their side," Nutter stated. "I've been down on the tracks on the scene with my staff. It is an absolute disastrous mess. I have never seen anything like this in my life." 

Nutter said that all law enforcement agencies are actively "engaged and involved" at the accident scene. 

Stay tuned to Fox News Channel for more updates on this situation.