|At least 200 of the 500 passengers evacuated by rescue workers were injured after two trains collided [Reuters]
More than 200 people have been injured after a subway train hit the rear end of another train in Shanghai, China's official state media has said.
No deaths were immediately reported, but pictures posted on Chinese websites showed bloodied passengers, some lying on the floor apparently unconscious, and others with injuries to their heads
The train systems operator reported put the number of injuried at 240.
Local authorities were investigating the exact cause of Tuesday's crash, the official Xinhua news agency said.
The Shanghai Metro said on the Weibo microblogging site that one of its trains suffered equipment failure at 2:10pm local time (0610 GMT), which then led station officers to manually direct approaching trains.
The collision occurred near the Yu Yuan station in central Shanghai at 2:51pm, according to online statements posted by the Shanghai Metro.
"Police and armed police have been dispatched to the scene to help with the evacuation," it said in a statement, adding that most of the injuries were minor and nine stations on the line had been closed.
Police cordoned off streets around the Laoximen, or Old West Gate station, near Shanghai's old quarter, where around a dozen ambulances could be seen.
The metro company said 500 passengers had been evacuated from the trains and the injured taken to hospital.
China's hugely popular microblogs buzzed with criticism of the authorities in the hours that followed Tuesday's crash, with many accusing the government of failing to ensure passenger safety.
"This is the consequence of rapid development. In the end we have to seriously consider if we want GDP or a happy life," one blogger posted.
"After this I won't dare take a subway," posted another.
The crash comes just months after a deadly high-speed rail crash killed 40 people and shook public confidence in China's vast rail network.
The crash in Wenzhou, a city south of Shanghai, was the worst ever to hit China's high-speed train network, raising questions about whether safety had been overlooked in the rush to develop the country's railway system.
A series of near misses have added to mistrust in the system - including one in July on the same line where Tuesday's accident occurred, in which a train took a wrong turn during peak hours due to a signal failure.
No one was hurt in the accident but passengers were alarmed by the mistake.
The Chinese government suspended approval of all new railway construction projects after the Wenzhou crash and cut the speed of trains running on newly-built high-speed lines.