Two PT service stations in Pattani province and another in Yala province were set on fire by what appeared to be coordinated bombings on Sunday night. One man was injured.
The Internal Security Operations Command (Isoc) reported the explosions all occurred around 11pm on Sunday.
They each targeted a PT station - one in Muang district of Yala and the two others in Sai Buri and Yaring districts of neighbouring Pattani. The blasts started fires at all three stations, Isoc's southern forward command said.
A man was injured by the bomb explosion in Sai Buri and was taken to Sai Buri Crown Prince Hospital, Isoc reported.
Security authorities set up blockades as investigators searched the bomb scenes and vicinity for evidence and more explosives. Several shops near the pumping station in Yala remained shut on Monday morning.