At least 73 people are now believed to have died after a train caught fire in Pakistan.

The train was travelling from the city of Karachi to Rawalpindi when at least three of the carriages burst into flames.

Pakistan minister for railways, Sheikh Rashid Ahmed, said the fire was caused by the explosion of a gas cylinder being used by passengers cooking breakfast.

As many as 40 people are also believed to have been injured.

According to officials cited in local media, many of the victims died as they tried to jump off the burning train.

Officials say the number of dead may still rise.

The accident happened near the town of Rahim Yar Khan in the south of Punjab province.

The train running from Karachi, across most of Pakistan to Rawalpindi, is the Tezgam - one of oldest and most popular train services in Pakistan.

It runs daily and takes 25-and-a-half hours.