Ten coaches have derailed, a Pakistani media reported on Sunday, adding that police have not yet announced the cause of the derailment.
Train traffic in the province has been halted as a result of the accident, and the cleanup could take up to 18 hours, the report said.
Sindh Chief Minister Murad Ali Shah expressed condolences over the loss of life in the incident and ordered immediate medical assistance to the victims. The Pakistani armed forces and Rangers have started immediate relief efforts at the site of the accident, and additional forces have been called to the scene. Military helicopters have also been dispatched for rescue operations.