Watch the BBC's David Shukman's report from the crash scene

The train was travelling from Munich to Hamburg when it went off the rails just before 11am (0900 GMT) on Wednesday in Eschede, 35 miles (50km) north of Hanover.

Nearly 300 people were injured, 200 of them seriously, officials said.

Rescuers fight to free survivors

The train, carrying some 400 people, was travelling at about 200 kilometres per hour (125mph) when the accident happened.

Officials say a car was found under the wreckage, which seemed to have been pushed some way along the tracks by the train before it derailed.

There are unconfirmed reports that the car had crashed through barriers on a bridge above the tracks before falling into the train's path.

Joachin Lindenburg of Celle police speaking about the crash

A police spokesman said 13 train carriages left the tracks.

The first four carriages of the train hit the support pillar of the overpass and telescoped into each other, witnesses said.

The bridge then collapsed onto the wreckage of the train.

But Klaus Rathert, the chief regional rescue coordinator, told the news conference that the front locomotive apparently decoupled from the passenger cars, causing them to derail and jackknife into the overpass.

The front locomotive traveled at least 500 metres from the scene of the derailment, through the Eschede train station, before the driver realised the passenger carriages had become detached, Mr Rathert said.

The station chief engaged the emergency brake, stopping the locomotive about two kilometers (more than a mile) from the scene, and thereby alerting the driver to the accident, Mr Rathert added.

'An almighty, great crash'

British painter and decorator Andrew Davidson, who has been working in Germany, witnessed the crash.

He told BBC1's 6pm News: "We were stopped on the road by the police because there had been an accident with a car coming off the bridge.

"Then out of nowhere came the express train and everyone just closed their eyes in disbelief," Mr Davidson said.

"The train had no chance to stop. There was just an almighty, great crash that seemed to go on for eternity.

"When the dust settled it was unbelievable. If you could picture a model railway track that had been smashed up by a child that is probably what it looked like.

"There were carriages on top of each other. Only one carriage came through the other side of the bridge.

"The bridge had come down on the last three coaches and totally flattened them. It was a real disaster."

More than 1,100 rescue workers were at the scene, including trauma surgeons, border patrol personnel, and 20 British soldiers and army doctors from a nearby base at Celle, fought to free victims.

Christian Krettek, of University Hospital in Hanover, told CNN that rescue workers expected the death toll to rise, and it was still unclear if there were more dead inside the shattered train cars.

A police spokesman described the scene as "a disaster zone".

'Worst crash in decades'

The BBC's Caroline Wyatt reporting from Bonn

This was the worst train crash in Germany for decades, according to officials, and the first involving an InterCity Express, or ICE.

More than 100 trains of this type were introduced on the national German railway network in the early 1990s and, until now, all have had an exemplary safety record.

Express trains carry up to 760 passengers in 14 carriages and can reach speeds of 300km/h.

The ICE has dramatically cut most journey times between German cities, with rail travel up more than 30% since the trains were introduced.