(aljazeera) - Investigators in China say preliminary enquiries have indicated that "human error" caused a pre-dawn crash between two high-speed passenger trains that killed at least 70 people and left hundreds of others injured.
The collision early on Monday took place near the city of Zibo in the eastern province of Shandong.
The accident left at least 400 injured, state media reports said, with at least 70 said to be in a critical condition.
It is the deadliest accident to hit China's railways in more than a decade.
Witnesses said one train, travelling from Beijing to the northeastern coastal city of Qingdao, derailed and slammed into another train travelling from Yantai to Xuzhou.
The collision caused 10 carriages from one of the trains to topple into a ditch alongside the tracks.
Al Jazeera's Beijing correspondent, Melissa Chan, says the number of casualties is expected to increase.
The country's rail minister, Liu Zhijun, had been despatched from Beijing to the collision site what our correspondent said was an indication of the severity of the incident.
It is not yet clear what caused the first train to come off the tracks.
Local media reports said the railway had begun operating on a new timetable on Monday.
A cargo worker at a nearby station was quoted by Reuters news agency as suggesting that the location of the trains, about 40 km from Zibo, indicated they were likely running at full speed at the time of the accident.
He said trains were already backing up near his station due to the collision.
One passenger described escaping the wreckage with her 13-year-old daughter through a massive crack in the floor of their carriage.
"We were still sleeping when the accident occurred," Xinhua quoted the woman, surnamed Yu, as saying.
"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."
China has one of the biggest and busiest rail networks in the world, carrying about one billion passengers a year, but has a relatively good safety record.
In one of the worst rail accidents in recent times, 126 people were killed and more than 200 injured when two trains collided in central China's Hunan province in 1997.
In January of this year a high-speed train ploughed into a group of rail workers conducting track repairs in eastern China, killing 18 people.
China has invested about $100bn in recent years to expand the capacity of its rail network, but analysts say the system has struggled to keep pace with the demands of the country's rapidly growing economy.