A 1,500-strong emergency crew was reported to be at the scene
At least 70 people have been killed and 400 injured, many of them seriously, after two trains collided at dawn in eastern China, state media have said.
A train travelling from Beijing to the summer resort of Qingdao derailed and hit the other, which was going from Yantai to Xuzhou.
Nine coaches of the Qingdao-bound train toppled into a ditch after the crash, outside Zibo city in Shandong province.
Just hours after the crash, an inquiry concluded it was caused by human error.
Two senior railway officials have already been sacked, according to the state-run Xinhua news agency.
The crash is the second major railway incident in Shandong this year.
In January, 18 people died near the city of Anqiu when a high-speed train from Beijing hit a group of track-maintenance workers.
Monday's crash is the worst in China since 1997, when 126 people were killed when two trains collided in central Hunan province.
It happened at 0443 local time (2043 GMT on Sunday) at a bend in the tracks in the suburbs of Zibo, about 70km (43 miles) east of the provincial capital Jinan.
Both of the passenger trains are likely to have been operating at high speed at the time of the accident, railway workers said.
It is not clear what caused the first train to derail and its carriages to topple into a ditch. The second was also derailed, but remained upright.
Witnesses said many passengers climbed out of the wreckage and wrapped themselves in bed sheets from the sleeper cars to protect against the early morning chill.
One passenger who escaped through a hole in a carriage with her 13-year-old daughter said she had been sleeping when the accident occurred.
"I suddenly woke up when I felt the train stopped with a jolt. In a minute or two it started off again, but soon toppled," she told Xinhua.
At least 70 of those injured in the crash were in a critical condition in hospital, Xinhua said. Four French nationals have been hospitalised with bone fractures.
Dozens are receiving treatment at the Zhoucun village People's Hospital, one of several involved in the rescue work, it added.
"Most are slight cases and more people are being sent in every hour," a hospital worker told Xinhua over the telephone.
"Some of our medical workers have gone out for rescue work, too."
Railways Minister Liu Zhijun has arrived at the scene to oversee the rescue effort, while Vice Premier Zhang Dejiang is also en route to assist, Xinhua said.
The city government of Zibo has sent a 1,500-member team to help and console the victims' families, the state-run agency reported.