Colombo, January 18: Six civilians were killed and a paramilitary guard was injured in an ambush by suspected Tamil rebels in a remote village in south-eastern Sri Lanka which had been infiltrated by the rebels, military sources said Friday.

The incident took place in Thanamalwila, 290 km southeast of the capital, late Thursday night. Reports from the area said the death toll could go higher.

The attack took place some 40 km from where rebels set off a claymore mine on a bus Wednesday, killing 27 passengers and injuring 63 others, and later shot dead six farmers. Troops have mounted a search operation for rebels who have infiltrated the area.

The Sri Lankan government officially terminated a Norwegian-backed six-year-old cease-fire agreement with the rebels. Fighting has escalated during the past two years and more than 5,600 have been killed during the period.