Thai police say attackers fired into security checkpoints in southern Thailand and killed at least 15 volunteer officers.
Police Colonel Thaweesak Thongsongsi, a superintendent in a police station in Yala province, said an unknown number of assailants used heavy weapons in the attack late on Tuesday night that also injured five volunteer officers.
The Bangkok Post newspaper reported that 11 of the victims were killed on the spot, while four others died at the hospital in Yala.
A Muslim separatist armed campaign has left about 7,000 people dead since 2004 in Thailand’s three southernmost provinces of Yala, Pattani and Narathiwat.
Police, teachers and other government representatives are often targets of the violence.
At least two other outposts in the area were also reportedly attacked, but there were no casualties.
A small explosive was found placed near an electrical pole to knock out power, and nails were scattered on a highway to disable vehicles entering Yala.
Several burning tires were left at a school.
According to the Bangkok Post, at least three rescue vehicles were also damaged, and several guns were taken by the attackers.
Tensions rose in August in the south over allegations that a southern man, 32-year-old Abdullah Esormusor, was beaten so badly during military interrogation that he fell into a coma. He later died of his injuries.
The army has said there is no proof of torture.
Mara Patani, an umbrella group representing some factions of the armed rebels, has called for international intervention after the Abdullah case – a request rejected by Thailand’s army.
Al Jazeera and news agencies