The four soldiers were helping villagers in Yarang district to repair a toilet at a local mosque when a group of eight armed men arrived in a pick-up truck and fired a hail of gunfire at them.
The exchange of gunfire, ended with three army rangers dead, while some of the assailants were believed to have been wounded in the incident as bloodstains were found along their escape route.
Meanwhile, National Security Council (NSC) Sec-Gen Paradorn Pattanathabut on Thursday said Thailand has not yet accepted the five-point demand of the Barisan Revolusi Nasional (BRN) militant group after receiving its 34-page official document via the Malaysian government coordinator.
He said the Internal Security Operations Command must thoroughly consider the demands while the Southern Border Provinces Administration Centre will also seek opinions from local residents, the civil society and academics on the BRN demands.
The agencies will later report their results to the Committee to Mobilise Policy and Strategy to Solve Problems in the Southern Border Provinces.
Gen Paradorn said the decision regarding the the BRN demand should be known before the next round of peace talks between the Thai government and the BRN scheduled about October 20.
The NSC chief today met with the Committee to Mobilise Policy and Strategy to Solve Problems in the Southern Border Provinces to assess the situation in deep South and consider budgets for security operations.
He said the meeting considered yesterday's killing of five police officers which was believed to be the work of oil and contraband smuggling syndicates operating in the areas who were dissatisfied with the serious crackdown by the authorities.
Gen Paradorn said the Army Region 4 commander reported to the meeting that more violent attacks are likely at the end of the month and that security personnel have been instructed to be on alert with pro-active operations as they remain the insurgents' targets.
National police chief Pol Gen Adul Saengsingkaew said the gunmen who killed five police officers have been identified as members of an insurgent group led by Majija. The faction is the same group which continued violent attacks in the far South during Ramadan and is believed to be linked with an oil smuggling ring. Police are now searching for all the suspects.