At least nine people were killed in an Indian train fire early Wednesday, reports said, just a week after 26 were killed in a train inferno in southeast India.

The fire ripped through three coaches of a train travelling from Mumbai to the northern city of Dehradun, resulting in thick smoke inside the airtight compartments while passengers were asleep.

"Three coaches caught fire this morning. All the passengers have been evacuated. At this time we cannot speculate the reason for the fire," senior Indian railways official Sharat Chandryan told news channel CNN-IBN.