At least 15 people were killed and 40 injured after a train derailed in Pakistan on Sunday, according to state public broadcaster Radio Pakistan.

The train derailed near Nawabshah in the southern Sindh province of Pakistan, the public broadcaster reported, adding that it was heading from Karachi to Havelian.

Pictures from the scene showed twisted wreckage and people clambering on the train's roof.

Pakistan's railway system has a poor safety record, with a series of deadly accidents in recent years a tragic reminder of the country's ageing infrastructure and safety standards.

This is a developing story. More to follow...