A soldier was killed and four others were injured in a terror attack in Thailand's deep south on Monday.

Chaidee Yaena and four other defence force volunteers were travelling in an armoured vehicle along a road when a planted explosive was detonated on the highway in Narathiwat province on February 12 afternoon.

Police Colonel Narawee Bin Wae-arong, superintendent of the Chanae District Police Station, said police were notified of the explosion at 3:35 pm local time.

Cops, soldiers, and medics arrived at the scene and found the armoured car lying on its side, around 100 feet from a large crater on the road.

Five people inside were wounded with two of them critically injured. They were rushed to the Chanae and Naradhiwas Rajanagarindra Hospitals, but one volunteer identified as Attaporn Prateep, died from his severe injuries.

Officers named the other four as Nusruding Madiyah, Chaidee Yaena, Bismee Samae, and the driver Imron Jehama.

Police Colonel Narawee said: 'The incident is suspected to have been carried out by members of extremist groups. There have been several similar incidents recently that resulted in the deaths and injuries of several defence personnel.'

Police also found scraps of an improvised explosive device, believed to be fashioned out of a gas cylinder, at the scene.

Chaidee, the leader of the group, said: 'I was leading the squad and we were driving from Chanae District Office to Changpuak Municipality to obtain a tent for the district office.

'When we were passing through the scene, the bomb was suddenly detonated. The explosion caused the armoured vehicle to bounce off the road and flip sideways.'

Authorities have cordoned off the area but said they have deferred investigations until the surrounding forests were cleared of possible insurgents waiting in ambush.

Islamic separatist terror attacks target the three southernmost provinces of Thailand - Yala, Pattani and Narathiwat - next to the border with Mulsim neighbors Malaysia. Thai state employees and infrastructure are often hit while attacks on civilians are rare.

Officials believe the conflict dates to 1909 when the British Empire, then in control of Malaysia and Singapore, struck a deal with Siam to incorporate the Muslim region into their country - against the wishes of the residents.

The region's culture is more similar to Malaysia and dramatically different to Buddhist Thais causing decades of tension that lead to the emergence of separatist groups fighting for independence in the 1960s.

The struggle has continued ever since with more than 7,344 people killed and 13,641 injured between January 2004 and March 2022.

The British Foreign & Commonwealth Office warns against all but essential travel to the region while Canada's government warns its nationals to 'avoid all travel' to the three provinces.