The police had gone to the site after railway officials reported the bomb, planted under tracks near a road intersection. The device exploded while the police were inspecting the tracks.

Chief Warrant Officer Chalad Boriphan and Sgt-Major Sulaiman Juden died at the scene and security volunteer Jirawat Phetmak was injured.

Police believe the explosion was the latest in a series of violent acts that have rocked the deep South since the beginning of last year, killing more than 1,000 people.

Fourth Army Area commander Lt-General Kwanchart Klaharn, who is also director of the Southern Border Provinces Peace-building Command, said yesterday that violence in the deep South had increased sharply since last year.

There were 3,027 cases of violence last year and so far this year there have been 3,300.

Of last year’s cases, 867 were directly related to security matters. This year security-related violence has been responsible for 1,017 incidents. Personal conflicts might have motivated the rest, he said.

Authorities arrested 79 suspects last year and have apprehended 88 so far this year. Narathiwat is the hottest spot for violence.

Fifteen of this year’s arrests are related to the murder of two marines at Narathiwat’s Ban Tanyonglimo last month.

Ninth Police Region Com-mander Lt-General Adul Saensingkeow said the 15 were from 34 arrest warrants issued by Narathiwat Provincial Court.

The two marines were beaten to death while being held as hostages by villagers following a drive-by shooting at a teashop. Many of the villagers accused the marines of involvement in the shooting.

Adul said the marines had fallen into a trap set by the militants who opened fire on the teashop, killing two Muslims and injuring four others.

Police are now searching for three major suspects believed to have been involved in both the teashop shooting and the murder of the two marines.