A passenger bus fell into a ravine and caught fire in southern Pakistan on Sunday, killing 40 people, a government official said.

The bus was carrying 44 passengers from Quetta in Balochistan province to Karachi in neighbouring Sindh province. The accident happened near the town of Bela, in Lasbela district.

Pakistan Bus AccidentPeople look at the burnt wreckage of the bus in Bela (Muhammad Saleem/AP)

Hamza Anjum Nadeem, assistant commissioner in Bela, said the bodies of 40 people, including women and children, were recovered. Four injured passengers were rescued.

“The accident happened due to over-speeding and the bus crashed into the pillar of a bridge. It caught fire soon after falling into the ravine,” he said.

He said the bodies were charred beyond recognition and were being taken to Karachi for DNA sampling. After identification, they will be handed over to the victims’ relatives.

Pakistan Bus AccidentAn official said many of the bodies were charred beyond recognition and the victims will be identified by DNA testing (Muhammad Saleem/AP)

Firefighters and workers from the Lasbela Welfare Trust and the Edhi Welfare Foundation carried out the rescue operation.

The chief minister of Balochistan, Mir Abdul Qudoos Bizenjo, expressed his sorrow for the loss of life and ordered authorities to provide the best medical facilities to the injured.

Road accidents in Pakistan generally happen due to violation of traffic rules, resulting in the deaths of thousands every year.