Two subway trains crashed in the Chinese city of Shanghai on Tuesday, rail authorities said, in an accident that reportedly injured several passengers.
Pictures from the scene of the crash posted on Chinese news websites showed bloodied passengers, some lying on the floor apparently unconscious and others with injuries to their heads.
There were no immediate reports of any deaths from the accident, which rail authorities said was caused by a signal failure.
The state Xinhua news agency said that local authorities were investigating the exact cause of the crash.
The incident comes as China is struggling to rebuild public trust in its vast rail system after a high-speed train crash near the eastern city of Wenzhou in July in which at least 40 died.
Xinhua said one subway train rear-ended another.
In July a signaling error on the same line saw a train take a wrong turn during peak hours, but no one was hurt.
Map of China locating Shanghai, where two subway trains crashed Tuesday, rail authorities said, in an accident that reportedly injured several passengers