At least 14 people have been wounded, two of them seriously, in a knife attack on a bus in Germany.
"We ask for your understanding that we can not provide any information about the identity of the suspect at the moment", the police added on Twitter.
"There are now no indications the man was political radicalised and no signs of a terrorist background".
It is understood that the man also left a "smoldering backpack" in the bus but the fire was promptly extinguished.
Policemen stand near a public service bus in Kuecknitz near Luebeck northern Germany, after several people were injured in the bus in an assault by a man wielding a knife on July 20, 2018.
The packed bus was heading in the direction of Travemuende, a popular beach destination close to the city of Luebeck, when a man pulled the weapon on passengers, Luebeck chief prosecutor Ulla Hingst said. Authorities have not yet confirmed the suspect's motive, but prosecutors said they had not ruled out terrorism. There were conflicting reports on the number of injured people and the severity of the injuries.
Several people were injured in an apparent knife attack in the norther German city of Lubeck.
German police said there was no indication that the attacker was politically radicalised. The attack took place at 1.47 p.m. local time (1147 GMT).
There was no evidence of any link to Islamist militancy and he was not a refugee.