An Amtrak passenger train derailed on a bridge over a major US highway in Washington state, sending part of the train crashing down onto Interstate 5 and killing several passengers, authorities have said.
Nearly 100 people were injured in the incident which happened during morning rush hour, around 7.30am local time.
A spokesman for the local sheriff's office, Ed Troyer, told reporters at the scene there were "multiple fatalities" but did not have a specific number to report.
He also said no motorists were killed, though some were injured when part of the train struck several vehicles.
Amtrak passenger Chris Karnes told a local news outlet that passengers were forced to kick out train windows in order to escape, because emergency doors were not functioning properly following the derailment.
"We had just passed the city of DuPont and it seemed like we were going around a curve," Mr Karnes said.
"All of a sudden, we felt this rocking and creaking noise, and it felt like we were heading down a hill."
"The next thing we know, we're being slammed into the front of our seats, windows are breaking, we stop, and there's water gushing out of the train. People were screaming," he added.
The derailment occurred on the first day that Amtrak trains began using a new route between the cities of Tacoma and Olympia, part of a project to reduce travel time, according to an October news release from the state's transportation department.
The new route takes trains along Interstate 5, eliminating a major choke point for passenger trains in Tacoma and allowing trains to reach speeds of 127km/ph, the department has said.
The train, which was scheduled to depart Seattle at 6am en route to Portland, Oregon, was the first to run along the new route.
It was not immediately clear whether the derailment was connected to the new route.
Amtrak confirmed its train was involved and said "some injuries" had been reported but did not immediately offer further details.
It said there were about 78 passengers and five crew abroad the train which derailed in DuPont.
A photograph posted by a Washington State Police spokeswoman showed an upside-down train car partially crushed on the highway, with a second car dangling off the overpass.
About 70 people were aboard the train, local news media reported, citing the state transportation department.
Authorities warned drivers to avoid the area, and the southbound lanes remained closed.
The National Transportation Safety Board said on Twitter that it was gathering information about the incident.
Washington Governor Jay Inslee declared a state of emergency due to "loss of life, injuries and damage to infrastructure."
US President Donald Trump tweeted that the crash "shows more than ever why our soon to be submitted infrastructure plan must be approved quickly."
Mr Trump said he will unveil his long-delayed infrastructure proposal after Congress passes its tax bill.
In a following tweet, Mr Trump said that his thoughts were with those involved in the incident.
My thoughts and prayers are with everyone involved in the train accident in DuPont, Washington. Thank you to all of our wonderful First Responders who are on the scene. We are currently monitoring here at the White House.
— Donald J. Trump (@realDonaldTrump) December 18, 2017
