The Narathiwat task force commander said the authorities would also tighten controls at border checkpoints along the Thailand-Malaysia border, Bernama reported.

Thai police said four people were injured, after coordinated bomb and arson attacks were carried out on 11 petrol stations in the border provinces of Narathiwat, Yala and Pattani. One of the injured was a policeman who was wounded by shrapnel while inspecting the scene at a petrol station.

The regional Thai internal security command said the attacks were carried out by masked armed groups on five PTT petrol stations in Narathiwat, four in Yala and two in Pattani, at around 1.10am.

There was extensive damage to property at the affected petrol stations and convenience stores.

Security agencies said the incidents were intended to send a signal linked to the coming general election and were not aimed at carrying out acts of terrorism.