Two trains crashed head-on in southern Germany early Tuesday, leaving at least four people dead and 40 seriously injured, the German news agency DPA said.
More than three hours after the crash, emergency services were still trying to reach people trapped in the wreckage.
Police spokesman Stefan Sonntag told The Associated Press the two regional trains crashed near Bad Aibling, in Bavaria before 7 A.M. and that several wagons overturned.
"This is the biggest accident we have had in years in this region and we have many emergency doctors, ambulances and helicopters on the scene," Sonntag said.
A spokesman for German federal police in Bavaria, Matthias Knott, said that the region was very inaccessible and making rescue efforts more difficult.
The crash took place near the river Mangfall in a densely wooded and hilly region.