The homeguard, who wear a distinctive light purple uniform, are a police force recruited and trained to guard their own villages.
The town of Vavuniya is the last major staging post before the southern front line that separates the government from rebel-held territory.
Fighting has now shifted to the far north, where the Tigers run a de facto state after losing large amounts of territory in the east to the Sri Lankan military.
A spate of land and sea clashes, ambushes and air raids have killed an estimated 4,500 people since last year.
Since 1983, the civil war has claimed the lives of nearly 70,000 people.