Seven Thai soldiers were killed as a bomb detonated under their truck while patrolling the Rangae district in the province of Narathiwat, police officials said Wednesday. Police suspect separatist insurgent were responsible.

The incident occurred at 3pm, near Bongo village in Rangae district, some 790 km south of Bangkok, where the Thai patrol ambushed a group of Runda Kampulan Kecil (RKK) insurgents, killing five of them. RKK is one of a dozen insurgent groups engaged in a separatist struggle in Thailand's three southernmost provinces - Narathiwat, Pattani and Yala.

Other bomb traps and nails placed in the vicinity prevented the authorities to immediately get to the location.

"This was an act of revenge for the deaths of their people two months ago," said Rangae Police Colonel Manot Anantarikul, blaming the attack on the RKK.

Violence against Thai authorities and Thai-Buddhists recorded a surge since retired army chief General Surayud Chulanont was appointed prime minister on October 1. Surayud promised to address the conflict through dialogue and reconciliation. Insurgents have stepped up their attacks in a desperate effort to drive a wedge between Thai-Muslims and Thai-Buddhists in the area.

A separatist movement began in the 1950s, sparked by government efforts to suppress the local culture and religion in the southern predominantly Muslim region but died down in the 1980s when more liberal measures were adopted.

Since the beginning of 2004, the escalating violence in the region claimed more the 2,100 victims, after a group of Muslim militants successfully raided an army depot and stole 300 war weapons.