The patrol unit, headed by Pol Lt Wichien Buanuan, deputy inspector of Yee Ngor police station, was travelling in a pickup truck on the Petkasem highway in Tambon Laharn when, out of a sudden, a bomb exploded about 15 metres behind the vehicle.
The force of the explosion from a 25-kg gas tank stuffed with explosives punctured a big hole by the roadside and scattered dirt on the road. But none of the policemen were hurt.
Police said that suspected militants might have hidden somewhere not far away from the scene and detonated the hidden bomb when the patrol car passed by the spot where the bomb was planted.
But the bomb exploded after the pickup truck had passed the spot by about 15 metres.