CHICAGO (WLS) -- Three people were killed and at least 50 were injured when a Chicago-bound Amtrak train struck a dump truck and derailed in rural Missouri Monday, police said.
Police said they first got calls about the Southwest Chief train, traveling from Los Angeles to Chicago with stops in between, striking the truck at about 12:43 p.m. in a rural area southwest of Mendon.
First responders arrived just after 1 p.m., police said. The incident happened at an "uncontrolled crossing" on a gravel road with no lights or electronic controls, according to law enforcement.
WATCH: Missouri State Highway Patrol update on Amtrak derailment
Amtrak officials said the truck was obstructing a public crossing, though police did not say if the truck was stuck on the tracks.
As a result of the impact, the seven of the train's eight cars derailed, police said.
"There was a jolt, and then I woke up, and then the train started rocking and flickering, and it just seemed like a normal jolt. But then I could definitely feel it come off the tracks, and then... it just kept going. And then it started to tip on my side," said passenger Rob Nightingale.
Two of the people killed were on the train, while the third was in the dump truck, police said. It was not immediately known if the fatalities on the train were crew or passengers.
Police said 270 passengers and about 14 crew members were on the train at the time of the crash.
Police said "multiple" people had been injured; earlier reports indicated at least 50 people were injured, but law enforcement officials did not confirm that number at a Monday afternoon press conference.
At least seven people have been taken to area hospitals.
Hedrick Medical Center said they have accepted four patients. They did not offer information on those patients' conditions.
University Hospital in Columbia, Mo., confirmed they have received three patients from the derailment, but did not offer any further details.
Video shows a desperate scene, with several derailed train cars on their sides. Passengers sat or stood atop those cars after apparently climbing out of windows.
"Local authorities are currently assisting customers and we have deployed Amtrak resources to assist. Additional details will be provided as available," the company said in a statement.
The train was scheduled to arrive at Union Station around 6 p.m., and it's unclear how many passengers aboard had Chicago as their final destination.
Mendon is in Chariton County, about 100 miles northeast of Kansas City.
Amtrak said anyone with questions about friends and family aboard the train should call 800-523-9101.
The National Transportation Safety Board is expected to arrive at the crash site in the morning. The agency is seeking the train's event record and other information.
This comes one day after an Amtrak train collided with a car in California, killing three people.
ABC News contributed to this report