An Amtrak train with 243 passengers derailed near Mendon, Missouri, on Monday, according to CNN. The train hit a dump truck at a public crossing around 1342 CT.

"There are approximately 243 passengers onboard with early reports of injuries," company officials said. "Local authorities are currently assisting customers, and we have deployed Amtrak resources to assist."

A passenger told The Daily Beast the derailment appeared to be a "mass casualty event."

Ron Goulet from Flagstaff, Arizona, said he was uninjured when the train hit a truck and jumped the tracks, resulting in the derailment.

"They've got every rescue helicopter and crew here from every direction.

"We are in Chariton County, Missouri. The train toppled over on its side. Every seat was sold out full, and they were packing people into the observation car because they were so full. There are plenty of people on back boards being taken [away] by paramedics," Goulet said.

The train was traveling from Los Angeles to Chicago at high speeds before the crash.