
The bomb was hidden near a small garden in the school grounds and set off remotely as the three soldiers came in range.
Separately, in Narathiwat's Chanae district, gunmen shot an election campaign staffmember of the Chart Thai Pattana Party candidate, severely injuring him.
The shooting took place at 10am on the Ragnae - Chanae Road in Lubo Lasoh village in Tambon Phadungmatra of Chanae district.Hawaetah Tahyeh, 51, was shot three times in the chest and once in his neck by a gunman using an AK-47 assault rifle.
Hawaetah was taking part in the election campaign for Niaris Jetapirom, who is contesting a by-election in Narathiwat's Constituency 2.
Hawaetah was riding in a pickup truck, the last in a 15-vehicle campaign procession. Police said insurgents also in a pick-up truck sped past the procession and opened fire at Hawaetah.
The Tuesday attacks came one day after Abhisit announced the formation of a new agency to oversee the three southernmost provinces.
The new civilian-led agency will be directed by a C-10 bureaucrat and have the power to transfer any government officials from the region.
It is not clear how the already complex security apparatus in the deep South will align itself under the new agency. Successive Thai governments have provided the military with an overwhelming mandate extending beyond traditional security to include development and reconciliatory effort.