WASHINGTON: At least five people were killed and dozens injured after a train derailed and overturned in Philadelphia late Tuesday.

Emergency personnel said six of the injured were in critical condition and 53 others were less critically hurt amid chaotic scenes after at least seven train cars, including the engine car, were crushed, turned over on their side or left upside down.

“It is an absolute disastrous mess. I have never seen anything like this in my life and most personnel will say that, as well,” Philadelphia Mayor Michael Nutter told reporters.

But Nutter warned that the casualty and injury estimates were only preliminary, hinting at the potential for a higher toll.

Hydraulic tools had to be used to remove passengers from some of the most badly damaged train cars, emergency personnel said.

Former US Congressman Patrick Murphy of Pennsylvania was on the train.

“Im ok. Helping others. Pray for those injured,” he tweeted. Delaware Senator Tom Carper was on board but got off just before the derailment.

Murphy, who was on board the restaurant car, said the train seemed to be going 60-70 miles (97-113 kilometers) per hour when it suddenly derailed and rolled. Passengers had to kick out a window to exit.

Some of the injured — many with bloodied hands and faces — were unable to move, Murphy said.

Initial reports had indicated that 10 of the train cars were affected by the accident.

Hundreds of emergency personnel, including firefighters and police, were deployed.

The Philadelphia Fire Department launched a large-scale operation to assist the 243 people aboard Amtrak Train 188 traveling from Washington DC to New York.

Five of the people aboard were crew.

The US Department of Homeland Security, the Southeastern Pennsylvania Transportation Authority, the Amtrak national rail service and others were involved in the search and rescue operation.

The National Transportation Safety Board said it was gathering information about the derailment.

Emergency personnel declined to speculate on the causes of the crash.

In a brief statement, Amtrak said all service had been suspended between New York and Philadelphia in the heavily-trafficked northeast corridor.

Crushed and overturned trains

At least one of the train cars appeared crushed and turned on its side. A large metal beam was rammed into another car, though it was unclear whether it had fallen onto the car or the car had crashed into it.

Part of the train turned into an L-shape.

The train had so much force at the time of the crash that it bent the sturdy rail tracks in at least one area.

Scores of emergency personnel used flashlights to comb the area for survivors in the dark, aided by helicopters hovering overhead.

The workers used ladders to climb over the flipped trains. Multiple fire engines, ambulances and police cars were deployed on the chaotic scene.

Train 188, a Northeast Regional rail service train, was scheduled to leave Washington at 7:10 pm (2310 GMT) and arrive in New York at 10:34 pm.

There are no seatbelts on trains operated by Amtrak, the national long-distance rail service.

“My thoughts and prayers are with all involved in the Amtrak train accident in Philadelphia tonight. Thank you to the first responders,” Pennsylvania Governor Tom Wolf said on Twitter.

“In contact with state and local authorities regarding train derailment in Philadelphia & closely monitoring the situation to assist.”

NBC News producer Janelle Richards was on board in a car that did not flip over.

“I was in complete shock. I think most people were. Once I realized what had happened, smoke started to fill the train car,” she told MSNBC.

“Everybody was moving as far away from that train as they could,” she added.