At least 65 passengers died when a train travelling from the Pakistani city of Karachi to Rawalpindi caught fire.
Minister for railways, Sheikh Rashid Ahmed, said the fire was caused by the explosion of a gas cylinder being used by passengers cooking breakfast.
According to officials cited in local media, many of the victims died as they tried to jump off the burning train.
District deputy commissioner Jamil Ahmed said some of the victims could not be identified due to the burning, and they would need to use DNA to find out who had died.
Prime Minister Imran Khan said he was “deeply saddened by the terrible tragedy” on Twitter, adding that he had ordered an “immediate inquiry”.