A roadside bomb hit a truck carrying five soldiers in Narathiwat province, the Bangkok Post reported. Police officers in the same province responding to a report of gunshots were ambushed by a bomb but escaped without injury.
Other bombings were reported in Yala province. Five police officers who were on their way back from investigating a series of explosions were injured by a bomb hidden in a culvert.
The explosion injured three civilians.
The rangers were killed by an explosion in the Sai Buri district of Pattani province.
Police in Yala province killed a suspected insurgent Friday. Officers were searching a village when the man ran to a house and opened fire and police fired back, killing him.
Southern Thailand has endured years of violence between security forces and ethnic Malays who are predominantly Muslim and seek separation from Thailand.