Officials say human error, rather than a technical fault, probably caused the crash near the northern town of Lathen.

The train collided with a maintenance vehicle left on the track on Friday, scattering debris across a large area.

German chancellor Angela Merkel visited the crash site to express her sympathy for the relatives of those killed.

"Words don't really help on a day like this, " Merkel told reporters.

"By being here I just want to show that our feelings are here in the region, especially with the relatives of the victims and the rescue workers".

Prosecutors in Germany are examining records of the train's radio communications to explain the cause of the crash. A communication failure is being seen as the disaster's likeliest cause.

The train, which floats on a monorail via a magnetic levitation system called maglev, was going at nearly 200km/h (120 mph) when it crashed near Lathen. The impact is thought to have flung the maintenance vehicle along the front and roof of the train.

Two workers were in the maintenance vehicle when it crashed. The train is said to have been carrying 30 passengers, of which 10 survived.

The track's operators say initial checks have not shown any sign of a technical fault.