Security has been beefed up in Songkhla's economic districts of Hat Yai, Sadao and Muang after intelligence indicated the nearby presence of a key insurgent figure.
Security sources in the three southernmost provinces reported that Mayakoh Lateh, a key operational figure in the southern violence, has travelled to the edge of Songkhla and there is a possibility insurgents are hatching a plan for attacks.
Along with the three key economic districts of Songkhla, officers also heightened security to the maximum level in the province's southern districts of Chana, Thepha, Na Thawi and Saba Yoi, which are next to the insurgency-plagued far South.
Teams have been deployed to patrol and set up checkpoints to prevent insurgents from carrying out attacks against security officials and civilians.
Security alerts also came after a car bomb attack in Thepha district on Tuesday wounded two policemen and destroyed a power transformer.
The bomb was packed in two gas cyclinders in the back of a pickup truck stolen from a retired teacher, Amata Samothanthawee, who was found hanged at his home in Saba Yoi district.
Two days later, four defence volunteers were shot dead at a school in Pattani's Yarang district. The perpetrators made off with four AK rifles.