"Acquiring some real estate does not mean much," Ilanthirayan said, referring to the army's advance into eastern rebel territories.
The military continued to clear Vakarai of mines and booby-trapped devices for a second straight day on Monday, military officials said.
About 20,000 people have fled the town in recent weeks to escape the fighting, which has claimed the lives of 500 combatants, according to the military.
The rebels have been fighting since 1983 to establish an independent homeland for Sri Lanka's minority ethnic Tamils after decades of discrimination under the majority Sinhalese-dominated government.
A 2002 truce still exists on paper, but has virtually collapsed since the resurgence of large-scale fighting last year.
On Sunday morning, army troops killed at least 18 Tigers as they tried to flee into rebel-held jungle in Batticaloa district, a military spokesman said.
Troops also found the bodies of at least 22 rebels killed in an army assault on Saturday.
The army took control for the first time in 11 years of a main road connecting the island nation's two main towns, Batticaloa and Trincomalee, during a the weekend's military action.