Two policemen were killed and three others injured by a bomb explosion on a road in Than To district of Yala province on Friday, police said.
The radio centre at Than To police station received a report of the bomb attack on Ban Rae-Ban Buathong road in tambon Ban Rae about 11.45am.
Police and a bomb disposal unit rushed to the scene and found Pol Sub-Lt Niyom Suwanmanee lying dead on the road.
Police also found four wounded policemen, Pol Sgt Maj Somnuk Duangnim, Pol Sgt Sithichai Kruebutr, Pol L/C Phanthep Aimsomboon and Pol L/C Paphon Dejanothai.
They all were taken to Yala hospital, where Pol Sgt Maj Somnuk was later pronounced dead.
The policemen, from Than To police station, were travelling on a pickup truck along the local road when a home-made bomb estimated at 30kg planted under road's surface was detonated, instantly killing Pol Sub-Lt Niyom and wounding his four colleagues.
The police truck was overturned by the blast, which left a crater two metres wide and one metre deep in the middle of the road.
Police blamed separatist militants.