Several people have been injured in an attack on a busy bus in the northern German city of Luebeck, police said.

A suspect has been arrested after the incident in the Kuecknitz district, police spokesman Duerk Duerbrook said.

Mr Duerbrook added that authorities are still trying to determine the circumstances of the attack.

Local newspaper Luebecker Nachrichten reported that two people had been seriously injured and 12 others received minor injuries in the incident.