Government forces were clearing landmines in the Thoppigala area which they captured from rebels on Wednesday, after months of heavy fighting, military officials here said.
But Tiger guerrillas fired mortar bombs and killed a soldier in the northwest of the island on Thursday morning, the defence ministry said, adding that other sporadic attacks were being reported in the rebel-held north.
The Liberation Tigers of Tamil Eelam (LTTE) fighters melted away from Thoppigala, a mountainous jungle area they dominated for more than 13 years, rebel spokesman Rasiah Ilanthiriyan told reporters from the north.
Tamil Tiger forces who remained in the east had gone into "guerrilla" mode, he said, adding that "winning the war was not about taking control of real estate."
"They are mentioning this as the end of the war in the east," Ilanthiriyan said.
"But that is not the truth. We have the experience in guerrilla tactics.
In fact, we have already changed our approach to guerrilla tactics.