A train has crashed into a bus carrying passengers at an unmanned railway crossing in southern Pakistan, killing 19 people and injuring 28 others, police said.

Superintendent Irfan Ali Sammu said the bus driver was at fault, and had begun crossing without assessing how close the train was. The dead and injured were on the bus and the train, he said.

The crash took place on Friday near the district of Rohri, about 290 miles north of Karachi.

The bus was torn into three pieces, and Mr Sammu said rescue workers faced difficulties throughout the night recovering bodies and rescuing the inured, who were strewn along a 435-yard stretch of track.

A child receives initial treatment in hospital
A child receives initial treatment in hospital (Pervez Khan/AP)

Women and children were among the dead and injured, and were transferred to two nearby hospitals, he said. Seven people died in hospital, and some of the injured were in critical condition.

Mr Sammu said the passenger train, called the Pakistan Express, was en route to Rawalpindi from Karachi.

Train accidents are common in Pakistan, mainly due to insufficient enforcement of safety standards, the poorly kept railway system and negligence by drivers of road vehicles.

Last November, a fire caused by a cooking gas stove swept through a train in eastern Punjab province, killing 74 people.

Survivors said it took nearly 20 minutes for the train to stop amid contradictory reports about the condition of the brakes.