At least six fatalities have now been reported.

An Amtrak train carrying approximately 78 passengers and five crew members has derailed 64km outside Seattle, Washington state. https://twitter.com/BenKennedyTV/status/942822606780223488 The vehicle, Train 501, was on the maiden day of a new €150m high-speed service between Seattle and Portland and was travelling at 128kph at the time. https://twitter.com/ABC/status/942835548665925632

It derailed while crossing a bridge over Interstate 5 near DuPont, Washington around 7:40am Pacific Time, causing at least one car to fall onto the freeway below.

https://twitter.com/Amtrak/status/942813003833073664

The Seattle Times is reporting that at least six are dead. CBS News reports that a total of 77 patients are currently being treated for injuries, with four classed as critical.

It is believed that no motorists driving on the freeway were killed.