Scores of passengers died in a train inferno when a fire tore through an overnight express in Pakistan. The blaze spread to three carriages after a gas canister exploded while passengers were cooking breakfast on the service between Karachi and Rawalpindi. Baqir Hussain, chief rescue officer at the scene, said that by mid-afternoon 73 bodies had been recovered from the remains of the train and another 40 people were injured. Most of the bodies were burnt beyond recognition, he said. Several of those who died had flung themselves from the moving train to escape the flames before the locomotive could screech to a halt. Many of the injured are in a critical condition with the death toll expected to continue to rise. Television footage showed flames pouring out of the carriages as people could be heard crying in the incident near Rahim Yar Khan district in Punjab province. "Two stoves blew up when people were cooking breakfast, the presence of kerosene with the passengers in [the] moving train further spread the fire,” the minister for railways, Sheikh Rashid Ahmed told Geo television "Most deaths occurred from people jumping off the train," he added. Stoves are banned on trains, but many passengers sneak them on to cook during long journeys, the minister said. Many of the passengers were heading to a conference organised by the Tablighi Jamaat Sunni Muslim missionary movement. "People were jumping off, some of them were on fire," a witness told the broadcaster. Prime Minister Imran Khan and President Arif Alvi each sent their condolences to the families of the dead. Mr Khan said he was "deeply saddened by the terrible tragedy," and added that he has ordered an immediate inquiry to be carried out. "According to information reaching us from the site of the accident, more than 65 people were killed and over 40 injured," the provincial health minister Dr Yasmin Rashid told AFP. The fire struck the popular Tezgam Express service, which takes around 26 hours to travel between the port and garrison city. “Terrible Tezgam train tragedy with gas cylinder carried by passenger exploding,” said Shireen Mazari, the human rights minister. “Prayers and condolences go to the victims' families. A tragedy that could have been avoided but ever since I can recall while travelling by train no baggage check or restrictions enforced.” An army helicopter was being used to ferry the injured and others were being sent to nearby hospitals in Bahawalpur and elsewhere in Rahim Yar Khan. Pakistan has an extensive rail network, but accidents are common. Railways have seen decades of decline due to corruption, mismanagement and lack of investment. The fire is thought to be at least the third serious incident on the nation's railways in five months. The most deadly of those saw at least 23 people killed in the same district in July, when a passenger train from the eastern city of Lahore rammed into a goods train that had stopped at a crossing. Accidents often happen at unmanned crossings, which frequently lack barriers and sometimes signals. Politicians have long promised they will use Chinese investment to overhaul and update the country's railways, but so far to no avail.