Four people were killed in an overnight bomb attack at a checkpoint in the southern Thai province of Pattani, an official confirmed Friday, agencies report.
“The culprits placed a bomb under a chair at the checkpoint killing four people,” Police Colonel Tanongsak Wansupha said.
Two of the volunteers were killed instantly and two more died in hospital Thursday night.
Two soldiers were injured in another bombing on Friday morning in neighbouring Narathiwat province.
No group took immediate responsibility for the two attacks.
The Muslim-majority provinces of Yala, Pattani and Narathiwat were part of the Sultanate of Pattani, a Thai vassal state, for several hundred years.
In 1909, the territory was divided between then-British Malaya and the Thai kingdom, in a treaty that formalized the region as Thailand’s three southernmost states.
An insurgent movement to create an independent state in the region has resulted in the deaths of 6,200 people and 11,000 injured since 2004.
In August, a roadside bomb went off in Bacho district in Narathiwat, killing a Thai soldier and injuring four others. A string of bombings hit Narathiwat and Songkhla in July and killed at least one person and injured over a dozen others.
Thailand is currently ruled by a junta, which seized power on May 22, 2014 in a coup following months of anti-government protests and violence in the country.
The Thai government held several rounds of talks with rebel leaders to end the conflict in the region. The talks, however, did not yield any results because of internal disagreement within both sides.