The pilgrims were crossing the tracks at a station in the state of Bihar when the interstate passenger train ran into them, police and Indian Railways officials said.

"Until now we have reports (from the ground) of 15 bodies and over a dozen others injured," local railway chief Arun Malik told.

"We suspect the toll may rise later in the day because we are not getting all the information from the site because of angry agitation by local people," Malik said.

Crowds converged on the Rajya Rani Express, setting carriages on fire and ransacking Dharhara station, some 200 kilometres (124 miles) from the state capital Patna, Malik said.

"Six carriages have been set on fire and the station has been ransacked by the mob. Our staff have fled the station fearing attacks," he said.

A senior railways official said it appeared the pilgrims were not aware of the incoming train.

"Two trains were already stationary on other tracks and the Rajya Rani Express was given permission to pass," Arunendra Kumar, chairman of the national railway board, told reporters in New Delhi.

"The accident occurred because some people left the platform of the station and came on the tracks," Kumar said.

There are hundreds of accidents on the railways annually.