At least 13 people were injured when two trams collided in Freiburg.
A man suffered serious injuries, and children were among the other injured passengers, a police spokesman said on Thursday.
Due to the force of the collision, a train was torn apart in the articulated part and fell off the track bed.
According to the fire department, the seriously injured man was thrown out of the tram beforehand.
Initially, the police had reported a total of 14 injuries.
There were many passengers on the trains in western Freiburg in the morning.
There were also 39 children with carers on the way, as reported by the German Red Cross.
The children were initially treated at the scene of the accident.
Some of them went to hospitals.
A total of 13 people were taken to clinics, as the aid organization reported.
Incorrect switch could be the cause
A switch may have been set incorrectly before the collision in rush-hour traffic.
The cause of the accident has not yet been finally determined, said the operations manager of Freiburger Verkehrs AG, Johannes Waibel, of the German Press Agency.
"But it looks as if there was a wrong run on a switch." There is construction work going on in the immediate vicinity on the route.
The police have started the investigation.
Operations manager Waibel said the two trains were in motion when the collision occurred.
The torn apart vehicle is around 30 years old and probably no longer usable.
The other train involved in the accident is about eight years old and can be repaired.
The accident caused disruptions on two lines.
Numerous rescue workers from several aid organizations and two emergency doctors were deployed at the scene of the accident.