A head-on collision between a passenger bus and a truck on a highway in southern Pakistan killed 58 people on Tuesday, police said. The collision ignited a fuel fire, and a rescuer later described how he carried out a survivor, a four-year-old girl, from the burning bus.

The cause of the accident near Khairpur district in Sindh province was most likely heavy fog, said police official Ghulam Jhokhio.

The bus, carrying about 70 people, had left Swat Valley and was en route to the southern port city of Karachi when it collided head-on with the truck, Jhokhio said.  The bus quickly caught fire after its fuel tank exploded, he added.

The fatalities included 14 women and eight children, said local hospital official Jafar Soomro and warned the death toll was likely to rise. Fifteen people were injured and in hospital, several of them in critical condition, he said.

Private Pakistani TV channels broadcast in live footage from the scene, showing rescue workers carrying he victims and policemen clearing the road.

Rescue officer Mohammad Ata described the inferno to Dunya TV as he held a little girl in his arms, and recounted how he pulled her out of the burning bus.

"She was sitting all calm in a seat when I got into the bus on fire," Ata said.

Deadly accidents are common on roads across Pakistan due to bad road infrastructure and rampant disregard of traffic laws. Over 9,000 road accidents are reported to the police every year, killing on average around 5,000 people every year, according to the Pakistan Bureau of Statistics.