A double-decker bus going from Betong district to Bangkok was set on fire by rebels after they ordered 11 passengers, the driver and an attendant to leave the bus.
The Bannang Sata police received a report of the attack at 2.20pm and rushed to the scene at Ban Kasod with explosives experts.
They found a double-decker bus operated by Siam Transport Co engulfed in flames. Firefighers were able to extinguish the fire in about 10 minutes, but the bus was gutted.
Police also found burnt tyres, a felled tree and spikes all over the road to block traffic.
Bus attendant Marorwe Ding said the Bangkok-bound bus had left Betong with 11 passengers, a driver and himself on board. At Ban Kasod, burning tyres on the road blocked their way.
When the bus stopped, 10-15 armed men dressed like soldiers emerged from the roadside jungle and ordered everyone off the vehicle. They then doused the vehicle with petrol and set it alight before leaving the scene, according to Mr Marorwe.
The attackers spoke in the Yawi dialect and did not harm anyone on the bus, he added.
Police suspected a group of insurgents led by Ahama Leubasar were behind the burning as they were active in the area. It was suspected that at least 20 people were involved in the operation.
