Authorities have ramped up security measures to their highest level in Songkhla's seven districts following a series of bomb attacks in Muang Yala municipality on Thursday night.
The blasts that rocked 30 locations in the province have injured at least 20 people since Thursday.
The districts which are under intense surveillance cover Chana, Thepha, Na Thawi and Saba Yoi, bordering the insurgency-plagued provinces of Yala, Pattani and Narathiwat, and the key commercial districts of Muang, Hat Yai and Sadao.
Security checkpoints have been established on main and minor roads to monitor vehicles.
In Hat Yai district, explosive ordnance reconnaissance (EOR) officers are using portable mobile phone signal jammers when checking vehicles parked in commercial areas.
Authorities are on the lookout for three motorcycles. They include a blue Honda Wave with a Pattani-registered licence plate, a black Honda Wave with a Surat Thani-registered licence plate and a black Honda Wave with a Pattani licence plate.
Meanwhile, six more bombs exploded in Yala’s Muang district yesterday morning, injuring two and bringing the total number of bombings in the province since Thursday night to 30.
Bomb disposal officers yesterday morning also collected and destroyed another three bombs.
Pol Gen Chamlong Suvaluck, commander of the Yala police, and bomb disposal officers went to examine the scene of the first bombing around 7am in tambon Sateng Nok. A ping-pong bomb had been thrown into a shop owned by Pimchai Wongwaiwisawakul, causing damage to the store, but no injuries.
The second location was at a morning tea shop owned by Klin Boonmak in the same tambon. One person was hurt and the shop was slightly damaged.
The third incident also occurred in tambon Sateng Nok at the Thongdee grocery store, causing damage to goods there.
Police found parts of a nine-volt battery and a mobile phone.
The fourth bomb was reported at 7.33am. It exploded at a junction near the Sateng Nok healthcare centre, injuring one person.
The fifth bomb was reported at 5.30pm. It exploded in front of a grocery shop in Yala's Muang district. The last bombing took place at the same shop at 6pm.
National police chief Somyut Pumpanmuang said five people were hospitalised. Most suffered only minor injuries.
Col Pramote Prom-in, spokesman for the Region 4 Internal Security Operations Command, said authorities estimated that 20 separatists were responsible for the bombing spree.
In nearby Narathiwat, four military rangers were ambushed in Sukhirin district at 11.10am yesterday, leaving one dead and the remainder injured. The attack took place on Ban Lubolasor Road in tambon Rom Sai while the rangers were on patrol.