Police suspect southern separatists led by Saudi Satapor were behind the attack.
Sergeant Major 1st Class Pradit Saranatrai, 52, and Private Yutthana Daraporn, 22, were rushed to Somdet Prayupparaj Yaha Hospital, where the former succumbed to his injuries in the emergency unit.
Pradit was leading the six-strong three-motorcycle team providing protection for teachers of Ban Katong School when the 5kg bomb exploded at 7.48am at Ban Kakong Bridge in Tambon Katong.
Yaha police investigators suspect insurgency leading Saudi Satapor, whose operates in Yaha and Katong districts, was behind the attack. Saudi is wanted for many national security cases including the bomb attack that killed two monks and injured two soldiers in Tambon Baro in May and another bomb attack that killed nine people in Tambon Katong in January.
Meanwhile a village headman assistant, Romeulee Maseng, 47, was shot at 2am today in Tambon Ai Yer Weng, Betong district. Romeulee had apparently stopped by a teashop on the Yala-Betong Road after running errands in Bannang Sata district. Two gunmen on a motorcycle also stopped at the teashop and one, pretending to be a customer, shot at Romeulee three times, hitting him in the arm, the stomach and the leg. Romeulee fired back but the gunmen escaped. Police suspect the attack stemmed from a local political conflict, as Romeulee had acted as a canvasser for the Tambon Adminsitrative Organisation President in the recent election, although they didn't totally rule out a personal conflict and southern violence.