At least nine passengers were killed when a passenger train caught fire in western India early today, officials said.

The train had departed from Mumbai and the fire broke out around 2.30am in the adjoining district of Thane, catching passengers in their sleep.

"We recovered nine bodies from three affected coaches," Railways spokesperson Sharat Chandrayan said.

"Four men and a woman died due to asphyxiation. Four more passengers were charred beyond recognition.

"Rescue teams have completed search operations, so we do not expect the death toll go much higher," he added.

The gutted coaches were removed and the train continued on to the northern city of Dehradun.

The fire was noticed by a gateperson near a crossing, after which the driver was alerted and stopped the train. The cause of the fire was not yet known, he said.

At least 26 people were burnt to death in a similar accident in southern India on December 28. India's railways operate more than 9,000 passenger trains that carry an estimated 20 million people daily.

- dpa