Security authorities were hit by synchronised attacks in at least 13 locations in the southernmost provinces of Narathiwat, Pattani and Songkhla on Wednesday night.
The Internal Security Operations Command initially reported that the attacks, mostly with grenades, happened at about 7pm in the three provinces. Some deaths and injuries were reported.
Seven of the attacks took place in Narathiwat.
Three grenades were hurled at a checkpoint in Yi-ngo district, a company in Si Sakhon district and villagers' houses in Waeng district.
About the same time, a bomb exploded in Rueso district. A grenade was fired at a special task force unit in Rangae district. A military base was attacked in Tak Bai district. A defence volunteers' group was ambushed in Sungai Padi district.
In Pattani, a grenade was thrown at the Kapho police station in Kapho district. More grenades were hurled at the Sarong police station in Yarang district and at a checkpoint in Mayo district.
In Songkhla, a grenade was thrown into the Chana police station in Chana district. Two bombs accidentally went off in front of a base of defence volunteers in Saba Yoi district and killed two attackers. A defence volunteers' group was ambushed in Thepha district.