At least 74 people were killed and scores injured on Thursday as a massive fire broke out on a moving train after cooking gas stoves carried by some passengers exploded in Pakistan's eastern Punjab province.

The train, Tezgam Express, was on its way to Lahore from Karachi when the fire broke out, destroying three bogies at Liaquatpur near Rahim Yar Khan, some 400 kms from Lahore.

District police officer Amir Taimur said that 65 passengers lost their lives after the fire erupted in three coaches.

Railway minister Sheikh Rashid Ahmad said that most of the victims belonged to the Tableeghi Jamaat (Islamic preachers) who were going to Lahore to attend a major annual congregation at Raiwind.

The railways minister said gas stoves carried by some passengers blew up when they were preparing breakfast on the speeding train in violation of the rules.

'Some of the passengers started making breakfast on small gas cylinders they brought with them which exploded and the fire engulfed the three coaches of the train,' he said.

Most deaths occurred from people jumping off the train, he added.

He said the toll could rise further as more than 40 passengers have suffered severe burn injuries.

Rescue operation is underway and army helicopters are helping to shift the injured to hospitals, according to a statement by the military.

Prime Minister Imran Khan expressed grief over the incident and directed authorities to provide the best medical treatment to the injured.

The authorities said they were still trying to identify the victims and that the lists of fatalities and of those injured were not ready yet.