Troops encountered stiff resistance from the rebel Liberation Tigers of Tamil Eelam (LTTE) as troops tried to move deeper into rebel territory, defence officials said.
The ministry said 30 rebels were killed and another 27 wounded in fighting since Thursday, while security forces lost four soldiers killed and another 14 wounded.
The latest casualty figures raise the number of rebels reported killed by troops since January to 6,363.
The military says 613 soldiers were killed during the same period.
The figures cannot be independently verified.
The military wants to dismantle the Tigers' de facto mini-state by capturing the town of Kilinochchi, 330 kilometres (200 miles) north of Colombo.
Government troops were said to be within striking distance.
However, the state-run Daily News said Friday the guerrillas offered stiff resistance and bot