A long-distance train carrying 243 passengers and 12 crew members derailed in the US state of Missouri.
The operating company Amtrak said on Monday that there were "first reports of injuries" - without first giving further details.
The train, traveling from Los Angeles to Chicago, collided with a truck at a level crossing in Mendon, derailing eight cars and two locomotives.
The truck blocked the level crossing in Mendon, a town about 150 kilometers northeast of Kansas City, it said.
The first photos and videos on social media showed wagons tipped on their side next to the tracks.
Some of the passengers who were able to free themselves were sitting on the overturned wagons.