An Amtrak passenger train derailed on Monday during its inaugural run along a faster route through Washington state, sending part of the train crashing down onto a major highway and killing an unknown number of passengers, Reuters reported quoting authorities.

The derailment caused “multiple fatalities,” Ed Troyer, a spokesman for the local sheriff’s office, told reporters at the scene, though he did not offer a specific number. The train struck several cars on the highway, he added, causing injuries but no additional deaths.

Seventy-seven people were transported to hospitals in Pierce and Thurston counties, the Tacoma-based CHI Franciscan Health healthcare network said in a statement. Four of them were considered “level red” patients with the most severe injuries.

UPDATE: The derailed Amtrak 501 train had begun new high-speed service today. Last week a mayor along the line predicted deadly accidents. First reports of casualties and injured. pic.twitter.com/hnGBYojpCe

— News_Executive (@News_Executive) December 18, 2017