More than 30 people were wounded, some critically, in the blaze which started when two gas stoves being used by poorer passengers to cook breakfast on Thursday morning blew up.
The fire, which was fuelled by cooking oil the passengers were carrying, engulfed three carriages of the train, which was carrying people from Karachi to a religious conference in Rawalpindi.
As smoke and flames tore through the train, desperate passengers threw themselves out of the moving carriages - many of them jumping to their deaths.
Children were among those killed in the blaze, according to local reports.
At least 65 people were killed and dozens wounded after a passenger train erupted in flames in central Pakistan on Thursday, a provincial minister said, AzVision.az reports citing AFP.
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.
"According to information reaching us from site of the accident, more than 65 people were killed and over 40 injured," provincial health minister Dr. Yasmin Rashid told AFP.
The wounded were being rushed to hospitals in the nearby city of Bahawalpur and elsewhere in Rahim Yar Khan district, she said, adding that only 18 of the bodies were identifiable.
"Terrible... train tragedy with gas cylinder carried by passenger exploding," tweeted human rights minister Shireen Mazari.
Local media reported that some of the passengers had been cooking breakfast when the cylinder exploded.
Mazari said the train was the Tezgam, one of Pakistan's oldest and most popular train services, which runs between the garrison city of Rawalpindi, adjacent to Islamabad, and the southern port city of Karachi.
Train accidents are common in Pakistan, where the railways have seen decades of decline due to corruption, mismanagement and lack of investment.
In July, at least 23 people were killed in the same district when a passenger train coming 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.
Prime Minister Imran Khan was elected last year on promises to build an Islamic welfare state but an ongoing economic slowdown and austerity measures have hampered efforts to invest in infrastructure and social programmes.
At least 10 people were killed and 16 others injured when a passenger train caught fire in Rahim Yar Khan district of Pakistan's east Punjab province on Thursday, local media and officials said, reports AzVision.az referring to Xinhua.
The fire erupted due to explosion of a gas cylinder inside the train on which a passenger was trying to make his breakfast, a railway official told Xinhua, adding that the fire engulfed three compartments of the train.
The fire has been extinguished from two bogies, while one is still ablaze, he said.
The official said that the death toll is feared to rise as some people saved their lives by jumping off the train, but a few might be left inside the bogie which is still under fire.
Local TV channel Geo reported that 10 people have been killed in the train Tezgam Express that was on its way to Punjab's Rawalpindi from southern port city of Karachi.
The injured people have been shifted to a nearby hospital, and the railway traffic will be restored after clearing of the wreckage from the track.
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