Two people were killed and five injured in a knife attack on a train from Kiel to Hamburg in northern Germany on Wednesday, Schleswig-Holstein's Interior Minister Sabine Sütterlin-Waack told dpa.
A man attacked passengers with a knife shortly before 3 pm (1400 GMT), before the train arrived at Brokstedt station, police said earlier.
Police officers arrested the suspected attacker shortly afterwards in Brokstedt. The motive was not clear.
The railway station was closed off by police.
Brokstedt is a small community about 60 kilometres north of Hamburg in the state of Schleswig-Holstein.