The clash occurred when a combined force of police and soldiers were searching a village in Raman district after a suspected insurgent with arrest warrant was reported hiding there.
Maroda Masila, 37, named in the warrant, was shot dead in a gunfight with the security force.
Mr Maroda was a fugitive for attempted murder and other charges.
At the crime scene, an 11-mm pistol was confiscated as evidence and for further investigation to determine whether it had been used in any previous insurgent violence.
Meanwhile, in the neighbouring province of Pattani, a bus on the Sungai-Kolok-Koh Samui route was shot three times by presumed insurgents on a motorcycle while the bus driver parked the bus to receive passengers in Saiburi district.
The passengers on board were unharmed, but the driver was wounded.
Authorities believed the shooting was an act of insurgency.