
Wicharn Sangsuwan, a paramilitary attached to Ranger Unit 46, died of sustained injuries at the Rusoh district hospital.
The 20 killogramme bomb was placed next to a concrete pole and set off as the rangers passes by.
Narathiwat's vice govenor, Niphan Naraphitakul, said the back to back bombing attacks often come at time of year when the Thai Army rotates their troops to the restive region.
Besides the patrolling unit, soft targets have also been hit by the militants. Niphan pointed to the last week twin bombing attacks that injured about 70 people in Yala's Sukirin district. The injured were part of some 300 village and tambon chiefs who gathered in Surkirin for their monthly meeting.
"The militants are trying to discredit the authorities in the region and make the areas ungovernable," Niphan said.
"We are keeping a close watch of the outer roads to prevent more roadside bombings. Special emphasis have been placed on the roads used by public school teachers travelling to and from schools in remote areas," Niphan said.