Four policemen escorting teachers and villagers were injured in a roadside bombing in southern Thailand on Thursday.

The group were travelling through the Raman district of southern Yala province to escort the teachers of Ban Na Toey School when a bomb hidden in the grass exploded on June 15 morning.

Police Sub-Lieutenant Abdulrosa Masaning, Deputy Crime Suppression Chief of the Kotabaru Police Station, along with Police Sergeant Major Natthawut Paduka and Police Sergeant Major Masaidee Karee experienced chest pains and ringing in the ears.

Police Lance Corporal Theeradol Signsrisanti sustained neck injuries, while an unnamed villager suffered chest pain after the blast.

The injured were taken to the Raman Hospital for treatment while the road section was cordoned off.

Yala Provincial Police chief Police Colonel Supakorn Phuengros said he led a team of explosive ordnance disposal officers, soldiers, and forensics staff to inspect the scene after receiving a report at 7:10 am. They found the police pick-up truck parked around 50 metres away from the blast site.

The police chief said: 'The vehicle's left side was perforated by shrapnel while the road was marred with a crater. Bits of bomb fragments and iron rods were strewn about the area.

'We believe the explosion was caused by insurgents who want to cause panic in the deep south.'

Police Lieutenant General Nanthadet Yoinual, the commissioner of Provincial Police Region 9, visited the injured officers at the hospital.

They told him they were conducting a routine patrol of the area and escorting the teachers when the 5kg homemade bomb was detonated remotely using a communication radio. They believe the explosion had been planned.

Nanthadet said: 'We have ordered the investigation team from Yala Provincial Police and Police Region 9 to swiftly inspect the scene, gather information, and identify the culprits responsible for the attack.'

Islamic separatists pushing for independence often target Thai state employees and infrastructure in the country's four southernmost provinces next to the border with Mulsim neighbors Malaysia.

Officials believe the conflict in Narathiwat, Pattani, Yala, and Songkhla dates to a deal in 1909 between the British Empire and then Siam to incorporate the Muslim region into the Kingdom, now Thailand.

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.