At least 10 people died and more than 40 were hurt when a freight train hit a passenger train head on in eastern Germany, authorities said on Sunday.
Wreckage was strewn by the tracks where the regional train derailed after colliding with freight wagons on Saturday night, collapsing compartments as it tipped on its side.
Police said they were investigating the cause of the accident, but that so far it was unclear what was to blame. Arriving on the scene, the top government official from the region where the crash occurred said human error was suspected.
Saxony-Anhalt state premier Wolfgang Boehmer said a stoplight was probably missed by one of the trains.
They crashed at around 2130 GMT in fog and freezing temperatures, travelling about 80 kilometres (50 miles) an hour.
Ambulance crews worked through the night to take victims to nearby hospitals in what was one of the country's worst train accidents in recent years. Eighteen people remained seriously injured and the death toll could rise, police said.
"As you can see we are all pretty speechless and shocked by the images we have seen," State Interior Minister Holger Hoevelmann said in a news conference.
The driver of the passenger train was killed upon impact, its operator said. The freight train engineer was injured in hospital, police said, adding that a criminal enquiry had begun.
Both trains were run by private operators. The freight train, carrying chalk, was owned by a subsidiary of Salzgitter, and the passenger train by France's Veolia which said the accident was its worst ever in Germany.
The train crash was Germany's worst since 2006, when a monorail hit a maintenance vehicle on a test track killing 23, and 1998, when a high-speed ICE train derailed leaving 101 dead.
German Chancellor Angela Merkel expressed her sympathy for victims and their families in a statement.
"My thanks go out to the rescue workers for their quick and tireless efforts," she said. "I am confident that all will be done to uncover the causes of this terrible accident."