Two rangers were killed and four others injured when separatist militants ambushed their patrol unit on a Pattani road on Tuesday night.
Nong Chik police station was alerted that a firefight had broken out on a road in Ban Don Na village in Tambon Bang Khao and dispatched reinforcements.
The four injured rangers were rushed to the Army hospital at Fort Ingkhayut Borihan for emergency treatment before being ferried to Pattani Hospital.
Police said the six rangers were patrolling on three motorcycles when they came under fire from a group of insurgents.
The rangers fired back and a five-minute gunfight ensued before the insurgents retreated and the rangers could radio for backup.
Pattani Taskforce commander Maj-General Jatuporn Klumpasut on Wednesday morning dispatched some 100 troops and police to the village to hunt for the attackers.