A dozen of wardens and two inmates were injured and were admitted to Songkhla hospital.
Primary investigation revealed that the inmates turned violent to protest prison action in narcotic checks in their living quarter, and overcrowding.
They said the living quarter was for 150 persons to live, but now it was added to over 200, thus causing it to overcrowded.
By late this afternoon, hundreds of police, soldiers were still keeping guard outside the detention area where smokes from burning is still visible.
Fire trucks arrived but still could not enter the fire scene as hundreds of inmates were still protesting and throwing rocks, sticks at authorities trying to come closer.
But Songkhla governor Narong Charoenkul and troop commander were holding meeting in the bid to end the riot before night falls.