Thai authorities on Thursday launched a manhunt after about 10 attackers killed five paramilitary Ranger soldiers at a Narathiwat checkpoint and wounded six civilians.
Security officials said the assailants opened fire and hurled pipe bombs near a residential area, then fled in a black pickup truck later found burned 21 kilometers away.
The attackers stole three AK-47 rifles, three bulletproof vests and three mobile phones; a 10-year-old boy remained hospitalized in stable condition and nearby homes were damaged by gunfire and blasts.
Prime Minister Anutin Charnvirakul called the assault a terrorist attack targeting government officials, as the military vowed to speed the investigation in Thailand's insurgency-hit deep south.
Narathiwat is one of three Muslim-majority southern provinces where a separatist conflict has simmered since 2004, killing thousands despite a lower current level of violence.