DEADLY AMBUSH: Soldiers inspecting the ambush site in Narathiwat province yesterday. A bomb overturned the soldiers' vehicle and rebels shot survivors who tried to escape. -- PHOTO: AFP

It was the single deadliest attack against the military in the region since June last year, when seven troops were killed in an ambush of a security team protecting a group of teachers.

In the latest incident, a powerful bomb overturned the soldiers' Humvee in Narathiwat province and left a huge crater in the road as the troops returned from escorting teachers to school.

Those who survived the blast were shot when they tried to escape, according to Lieutenant-Colonel Kannart Nikornyanont, one of the top provincial military commanders.

Militants attempted to behead all eight soldiers. They decapitated the top officer in the group and left the others with gaping stab wounds to the neck, he said.

'They cut off the head of one of the soldiers, while the rest suffered deep wounds that left their heads partially severed,' Lt-Col Kannart said.

The officer's head was left near the wreckage of the Humvee.

Four soldiers travelling by motorcycle with the Humvee vehicle managed to escape injury after a 15-minute gun battle with the militants, he said.

The attack happened around 9.40am in the Chanae district of Narathiwat, one of three provinces along the Malaysian border that have been dogged by four years of separatist violence.

The convoy was part of a security detail that had escorted teachers to their school yesterday morning, Lt-Col Kannart said.

Armed soldiers escort teachers to and from school every day in Thailand's south. Educators are often targeted by militants, who view teachers as symbols of Buddhist Thailand's domination of this Muslim and ethnic Malay region.

Thai Prime Minister Surayud Chulanont said the latest deadly ambush was not an escalation in the conflict. It was instead a routine ambush with an unusually high number of victims, he said.

'This kind of clash can happen any time. It is not a serious escalation' of the conflict, he told reporters.

More than 2,800 people have been killed since the rebellion began in January 2004, with killings growing more frequent and brutal.

Former prime minister Thaksin Shinawatra's heavy-handed tactics in dealing with the insurgency were widely blamed for exacerbating the unrest in Yala, Pattani and Narathiwat provinces, but he was ousted in a military coup in 2006.

Thai generals and General Surayud have vowed to quell the insurgency with peace overtures to the rebels, an apology over past abuses, the reform of Islamic schools and tougher security. Nevertheless, killings in the south have grown more frequent and brutal, with both Buddhists and Muslims targeted every day.

AGENCE FRANCE-PRESSE