Five teachers and two security volunteers were injured by a roadside bomb that exploded in Yala's Muang district on Monday morning, police said.
A homemade bomb, weighing two to three kilogrammes, was placed under a road sign and was detonated by remote control as a group of teachers and their security escort passed the spot, police said.
The explosion caused a hole about 80cm deep and scattered debris around the area.
The seven injured victims were admitted to Yala hospital.
Over 4,500 people have been killed and about 9,000 hurt in the southern border provinces since separatist militants started violence afresh in January 2004. (source)