The explosive was hidden beneath an area near a temporary bridge and was set off by mobile phone, pieces of which were found at the scene, police said.

In Narathiwat, authorities in Rusoh district rounded up eight suspects from 11 locations during a mop-up operation, while in Si Sakhon district, a military checkpoint for passing motorbikes came under gunfire, but no injuries were reported.

Police are still hunting for six suspected militants who were seen setting fire to five patrol boats belonging to the Pattani Fisheries Association.

An eyewitness said two of the men in black hoods told the villagers that they had come to "burn the government's property" and that the locals would be unharmed if they did not resist. Damage is estimated at Bt5.4 million.

The parents of the two young Muslims shot dead in Pattani's Ban Bana on April 13 by a group of soldiers are demanding Bt4 million in compensation for each of the boys.

The three boys who were wounded are each asking for Bt1.5 million to Bt2 million.