BANGKOK: Four Thai army rangers were killed Friday when a roadside bomb tore through their truck as they were securing a road for teachers, an army official said, the latest carnage in an insurgency roiling the kingdom’s far south. The blast in Pattani province also wounded six, including one civilian, said deputy army spokesman for the south, Colonel Yuthanam Petchmoang. The group was on a routine early morning patrol to clear a road used by teachers in Sai Buri district when the bomb erupted, tearing their silver pick-up truck in two and carving a crater into the rubble-strewn road. The explosive was tucked into a drainage tunnel beneath the road and detonated after four of the ranged stepped out of their truck to inspect the site, the southern Internal Security Operation Command (ISOC) said in statement. “The incident was aimed to incite unrest and violence in the region without regard for the safety and livelihood of residents,” it added.