Police took a suspect into custody in Michigan on Friday after four people were stabbed aboard an Amtrak train in the town of Niles, a police dispatcher said.
None of the victims had been killed in the attack, a dispatcher for the Niles Police Department said. Police could not immediately describe the conditions of the victims, nor give any further details on the incident or suspect.
Niles, a town of about 12,000 people, is about 10 miles (16 km) north of South Bend, Indiana.
Amtrak said the incident took place on Train 364, the Blue Water service, which runs daily between Chicago and Port Huron, Michigan, while the train was at the station in Niles.
The company gave no details of the incident, but said in a statement a person was in custody and that the Amtrak police department is assisting in the investigation.
The Chicago Sun Times newspaper quoted a Twitter user who said four people were stabbed in the next carriage along from him, and who uploaded a photograph of a man in a gray jacket lying in handcuffs on the floor of the train.
"Crazy world we live in. Some man just stabbed 4 people one car away from me on the train," said the user, @Chris_Maynard.
Amtrak said the train had been traveling to Port Huron at the time of the incident, and it said the company is working to arrange alternate transport for 172 passengers.