Five Thai paramilitary soldiers were killed and six civilians wounded after armed assailants attacked a security checkpoint in Thailand's southern province of Narathiwat, authorities said on Thursday, in one of the deadliest assaults on security forces in recent years.

The attack took place on Wednesday evening at the Buketa Sami checkpoint in Narathiwat, one of Thailand's three southern border provinces affected by a long-running separatist insurgency.

According to the military's Internal Security Operations Command (ISOC) Region 4, around 10 attackers dressed in black clothing and black brimmed hats arrived at the checkpoint in a pickup truck and on motorcycles before launching a coordinated assault.

The attackers opened fire on members of Task Force Ranger Regiment 45, who were guarding the checkpoint, while also throwing pipe bombs during the attack.

Following the assault, the gunmen seized three AK-47 rifles, three bulletproof vests and several mobile phones before fleeing the scene.

Security forces later located the pickup truck believed to have been used in the attack approximately 21 kilometers from the checkpoint. Authorities said the vehicle had been abandoned and set on fire.

No group has claimed responsibility for the attack, and officials have not announced any arrests.

Thailand's government condemned the assault, describing it as an act of terrorism that threatened national security and efforts to restore peace in the country's troubled southern region.

Government spokeswoman Rachada Dhnadirek said the attack posed "a serious threat to national security" and undermined ongoing attempts to revive the peace process.

The Thai army paid tribute to the five fallen soldiers, saying their "service and sacrifice will be remembered and honoured with the highest respect."

The checkpoint attack came just one day after a car bomb exploded outside the former Tanyong police station elsewhere in Narathiwat province.

The explosion injured a police officer and caused damage to the building. Authorities said they are searching for two suspects who were seen fleeing the area on a motorcycle.

According to local media, it was the first recorded car bombing in Thailand's southern border provinces this year.

The latest incidents have heightened concerns over a resurgence of violence in the predominantly Muslim southern region.

Narathiwat, along with neighboring Pattani and Yala provinces, has been the center of a separatist insurgency since 2004.

The conflict, driven by ethnic Malay Muslim insurgent groups seeking greater autonomy or independence from the Thai state, has claimed the lives of more than 7,000 people, including civilians, members of the security forces and insurgents.

Peace negotiations between the Thai government and the Barisan Revolusi Nasional (BRN), the main separatist organization, were expected to resume in June following an increase in violence.

However, talks have repeatedly stalled over disagreements concerning self-governance, security arrangements and political representation, leaving the decades-long conflict unresolved. (ILKHA)