Three paramilitary rangers and a housekeeper were killed in an ambush in Thailand's restive southern province of Yala on Saturday morning, Thai media reported.

The attack took place on a road in Yala's Muang district at about 6 a.m. local time.

When police rushed to the scene, firefighters were trying to put out a blaze in a pickup truck.

Lying on the road near the burning vehicle were the dead bodies of three rangers and that of a housekeeper at the ranger camp.

Witnesses told police that the rangers and housekeeper were traveling on the pickup to a fresh market in Muang district when gunmen hiding in a roadside forest sprayed bullets at them with M16 assault rifles and 9 m.m. handguns.

The four victims were shot several times in the heads and bodies and died on the spot.

The attackers stole the M16 assault rifles of the rangers and then set fire to the pickup truck and fled.

Police believed that the attackers were members of the southern separatist movement.

More than 5,000 people have been killed and over 8,400 hurt in the three southernmost provinces of Yala, Pattani and Narathiwat since violence erupted in January 2004, according to Deep South Watch -- an agency that monitors the conflict in the southernmost provinces.