Lt Gen Walit Rojanaphakdi, commander of the 4th Army Region, said that the Betong bombing might have resulted from the authorities' negligence.
He ordered an investigation of the theory.
Regarding the explosion that killed three people, injured more than 40 others and damaged much property, Gen Walit said if the cause was a security system, it would be corrected, but if it was a human error, those responsible would be punished.
He said that the incident could at least partially result from negligence by the authorities.
In response to violent incidents in the far South during the Ramadan season of fasting, the 4th Army Region commander said Army chief Gen Prayuth Chan-ocha ordered full-scale security measures and police, soldiers and administration to integrate their operations to ensure safety for people and property.
They have clear shares of areas under their protection he said.
Besides, concerned authorities are trying to inform local people of distorted religious beliefs used by insurgents and to convince them not to support any party that abuses religious beliefs, the regional army chief said.
Gen Walit also said that violent attacks were aimed at the economy and weak targets while the authorities were trying to stimulate the economy to boost confidence.
It would take time to handle violence in the far South and boost local residents' confidence in the authorities, their public services and their fair law enforcement, he said.
Asked if violent incidents would have any impact on the annual military reshuffle, Gen Walit said the reshuffle depended on the decisions of his superiors.