Security personnel in the Deep South are placed under maximum alert after the bomb attack in Yala that killed three civilians and injured at least 18 others.
Fourth Army Commander Lt Gen Piyawat Nakwanich ordered maximum alert and apologised the southern people for failing to prevent violent attack.
Although security has been tightened but the perpetrators still could manage to slip in to create violence, he said.
He condemned the attackers and said security officials now have information of the perpetrators who might be the new recruits.
Security officials were looking into survellance video cameras to track them down, he said.
Lt Gen Piyawat said motive of the bomb attack might also stemmed from black market business.
The bomb attack at Phimolchai market in Yala municipality occurred at 6.30am today (Jan 22).
Pol col Pravit Choseng, superintendent of Muang Yala police station, said initial examination of the bomb scene found that the perpetrator parked a Honda motorcycle in front of a pork stall and left.
The bomb went off five minutes later, killing two people at the scene. Another died at Yala Regional Hospital.
The Internal Security Operations Command said Yala town had been free from violent attack for a long time, saying the violence was the first time in many years. They believed the attack was intended to sabotage the economy of the South.