Reports reaching here said that a passenger bus carrying devotees from Sehwan Sharif was on its way back to Cheecha Watni from Jaey Shah Noorani Dargah.
When it reached near Dadloi, its tyre bust and the bus collided with a trawler coming from the opposite direction.
The 13 people were killed on the spot. Among the dead were drivers of both the vehicles.
The 20 injured passengers were taken to Sukkur and Pano Aqil hospitals.