YALA - SUSPECTED Islamic militants shot dead a Buddhist couple and set their bodies on fire Thursday in the latest gruesome attack to hit Thailand's troubled south, police said.

A bloody six-year separatist insurgency in the kingdom's southernmost provinces along the Malaysian border has killed more than 4,100 people and wounded thousands more.

Police said a 51-year-old man and his wife, 42, were on a motorcycle on their way to work at a telephone company when attackers gunned them down in provincial capital of Pattani.

The militants then doused their bodies with gasoline and torched them in the middle of the road, police said.

The insurgency erupted in January 2004 but tensions had bubbled under the surface in the south since predominantly Buddhist Thailand annexed the former Malay Muslim sultanate in 1902.

The shadowy militants never publicly state their goals and use a range of methods in their attacks, ranging from bombs and shootings to burnings, beheadings and even crucifixions.