Police say a schoolbus has veered off the road and into a ditch in the Black Forest of southwestern Germany, injuring 12 children, two of them seriously, according to AP via International Herald Tribune.

They say the bus went off the road on a sharp curve and into a stream-bed early Tuesday morning.

Police say it is not immediately clear what caused the accident. Further details on the ages of the students and the condition of the bus driver are not immediately available.