Eleven civilians, including six children, were also injured, according to police officials.
The LTTE could not be reached for comment.
The attack came a day after govenment forces killed around 16 Tiger fighters in a naval attack near Mullativu, the fighters' last base, off the northeastern coast of the country.
Sri Lanka's military has captured much of the Tiger's territory in recent weeks with Kilinochchi, the Tiger's de facto capital, falling earlier this month.
Mahinda Rajapaksa, Sri Lanka's president, has said that his troops are now on the verge of victory and that he will not accept anything short of total surrender from the Tigers.