MUMBAI: Three commuters hanging onto the outside of a train in Mumbai were killed on Thursday when they were hit by an iron pole in the latest accident on India's overcrowded railways, police said.

At least 12 other people on the train were injured when they fell off between stations as passengers desperately tried to stay aboard as the engine travelled through the city's suburbs.

"It appears that this unfortunate and freak incident is a result of extreme overcrowding on the train," the railway network said in a statement.

An unnamed police official told the Press Trust of India agency that two of the three commuters died immediately when they were hit by the iron pole between stations. A third person died later of his injuries.

Other commuters who were clutching onto the outside window grills of the train fell in a heap beside the tracks in the accident.