(Reuters) - Two people were killed and several others injured when a 33-year-old stateless Palestinian man attacked them with a knife on Wednesday on a regional train travelling between Kiel and Hamburg in northern Germany, authorities said.

Police in the state of Schlewsig-Holstein on the Danish border said the man, who was himself lightly injured, was being treated in hospital. He was arrested at a train stop in the village of Brokstedt.

Three others were seriously injured in the attack and four were lightly injured, authorities said.

There was no information yet on the motive for the attack, police said. Regional broadcaster NDR, citing sources on the investigation team, reported that the man, who came from Gaza eight years ago, had a criminal past, and there was no evidence of a political motivation.

Police were investigating at the train station in Brokstedt, the German railway Deutsche Bahn said on Twitter, adding some services between the two cities had been cancelled.

Reuters photographs from the scene showed forensics experts gathering evidence on the station platform.

Federal and state police were working together on the investigation, state interior minister Sabine Suettelin-Waack said in a statement.