According to Atac, Rome's public transport company, the stationary train was struck from behind by another travelling at high speed. Later, passengers emerged from the subway claiming the driver of the second train appeared to have run a red light.

"Earlier out train stopped in a tunnel for a few minutes waiting, then we moved and the crash occurred. We heard a loud noise, tehn there was a black out. We opened the emergency doors. "

Officials said the passenger killed and the most seriously injured had been in the last carriage of the halted train. Rome mayor Walter Veltroni, said officials investigating the cause were trying to determine if human error was to blame or if something had gone wrong with signalling at the station.

"The train behind hit the other train, it's still unclear why the crash happened, those trains are new, so they work perfectly."

The Fire department has identified the victim as a 30-year-old Italian woman. The driver of the moving train was pulled out alive from the rubble. Earlier reports said he had died at the hospital, but this was later denied.