At least seven people have been killed and 65 injured when a train carrying almost 250 passengers derailed near the US city of Philadelphia.
Firefighters said six of the injured were in a critical condition.
The scene was a crumpled mess after seven train cars, including the engine car, were crushed, turned 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 said.
Mr Nutter said the death toll could rise from the derailment.
Officials declined to speculate on the cause of the incident, though some experts suggested the crash may have been caused due to a track defect or wheel failure.
Amtrak said there were 238 passengers and five crew members on board the derailed number 188 train, en route from Washington to New York.
“Initial reports are that several passengers have been injured and taken to local medical facilities for treatment,” Amtrak said in a statement, adding that services along the whole north-east train corridor between New York and Philadelphia had been suspended.
Hydraulic tools had to be used to remove passengers from some of the most badly damaged train cars, firefighters said.
“I’ve never seen anything so devastating. They are in pretty bad shape,” said Fire Commissioner Derrick Sawyer, referring to the train cars.
“You can see they completely, completely derailed from the track, destroyed completely and they’ve been overturned completely.”
Former US Congressman Patrick Murphy of Pennsylvania was on the train which he said seemed to be going about 100 to 110km/h, when it suddenly derailed and rolled.
Passengers had to kick out a window to exit.
“Im ok. Helping others. Pray for those injured,” Mr Murphy tweeted.
“Some of the injured, many with bloodied hands and faces, were unable to move.”
The US Department of Homeland Security, the National Transportation Safety Board, the Southeastern Pennsylvania Transportation Authority and along with Amtrak were involved in investigating the causes of the crash.
– with agencies