15 people were killed and over 60 were injured after two trains collided in India's West Bengal state on Monday, local media reported. 

The accident occurred near the Rangapani railway station in the Phansidewa area of West Bengal's Darjeeling district at around 9:00 a.m. local time when a freight train crashed into the "Kanchanjunga Express" passenger train that was traveling to West Bengal's capital, Kolkata.

The chairperson of the country's Railway Board, Jaya Varma said a preliminary inquiry into the collision has suggested that it occurred due to a "human error," as the driver of the freight train, who died in the accident, failed to follow the signal and rammed into the passenger train from behind.

She said rescue work had been completed, and authorities are working to restore traffic, with the damage less extensive than initially feared. 

Three carriages of the passenger train were driven off the rails. It was not immediately clear how many passengers were on board at the time.

Prime Minister Narendra Modi has offered condolences for the loss of lives and ordered officials to follow up on the situation. 

(With input from agencies)