At least five people have been killed and at least 60 injured when an Amtrak passenger train derailed near the American city of Philadelphia.
Up to 10 carriages of the Washington-New York Amtrak service reportedly went of the track.
Emergency officials and fire-fighters were at the scene looking for passengers who may be trapped in the wreckage.
About 240 people were on board Train 188, according to NBC10.com. The cause of the accident was not immediately known.
Patrick Murphy, a former US congressman, tweeted that he was on the train when it crashed.
"Im on @Amtrak train that just crashed. Im ok. Helping others. Pray for those injured," he wrote.
Im on @Amtrak train that just crashed. Im ok. Helping others. Pray for those injured.— Patrick J. Murphy (@PatrickMurphyPA) May 13, 2015
Associated Press employee Paul Cheung said he was fortunate to be at the back of the train and the front of it ``looks pretty bad'', the news agency reported.
Mr Cheung added he saw "some people mangled up".
Police asked people to stay away from the crash scene so rescue crews had more room to treat the injured.
The area has been sealed off.
Amtrak is a national publicly funded rail service, serving tens of millions of people every year.